Perspective Chapter: Crime Scene Investigation in Criminal Behavior Cases – Forensic Biology, Forensic Entomology and Forensic Entomotoxicology

Abstract

Branches of forensic science are used to determine the samples used in solving suspicious death cases and the criminal behavior of the suspect. Forensic biology, forensic entomology, and forensic entomotoxicology are just three of them exterior surfaces of cars, are of interest to forensic biology. Forensic entomology is an interdisciplinary science that contributes to the solution of forensic cases by examining the life cycles and successions of arthropods on corpses. The first question that forensic entomology seeks to answer is when the person died. Clarifying the questions of how and where the person was killed will shed light on forensic investigations. The field of forensic entomotoxicology is to determine the alcohol, narcotic substances, and poisons used by the person before his death by toxicological analysis of arthropods fed on corpses. In this section, the journey of the samples collected from the crime scene to the laboratory in the fields of forensic biology, forensic entomology, and forensic entomototoxicology will be followed.

1. Introduction

In this chapter, crime scene investigation in the field of forensic biology, forensic entomology, and forensic entomotoxicology will be mentioned.

Forensic biology is a science field that has support to the forensic system by investigation of body liquids such as blood, semen, saliva, feces, urine, buccal swap, and vaginal swap. DNA exists in every body cell, and therefore, DNA is available on each biological material where the crime scene [1]. Collecting and sending every sample that can contain DNA material is important for forensic biologists to solving crimes.

1.1 Crime scene investigation in forensic biology

The first step of resolution of subjects including crime behavior is crime scene investigation. We can understand that the crime scene investigation is not only the first step of resolution of crime but also the key point of it from “Every Contact Leaves a Trace” sentence is expressed by Edmond Locard [2, 3].

Crime scene work is a scientific work. Therefore, during education of crime scene investigation, analytical thinking, making observations, practical thinking, and quick interpretation of the data obtained trainings are also given. Biological and physical samples are collected from crime scene so that identification work can be carried out in the laboratory [4]. Collected samples are findings. Findings are considered as evidence as a result of laboratory examination. Not all findings are evidence. In suspicious deaths, investigation that will be done at the crime scene is usually once; therefore, it should be done very carefully and in the correct form. In order to understand the behavior of crime at the scene, a crime scene investigator should walk around scene and should think about the kind of case and which samples may be evidence. Once the crime scene investigators have decided what to collect and the pattern of criminal behavior that is to collect samples from crime scene easy for a crime scene investigator who has the ability to actively, fast, and practical thinking. Odors and sounds should be taken into consideration very carefully at the crime scene. Security of crime scene should be provided for both physical and biological materials and crime scene investigators. The investigator should take pictures of materials and samples being answers to the questions of 6 W (Who, What, When, Where, Why and How) and should also record on video, draw sketches, make measurements, save notes, and bring these materials and samples to the laboratory [5, 6].

1.2 Importance of taking pictures, recording videos, and documentation

Taking pictures and recording videos have a vital importance in investigation of crime scene. They are important for both documentation and preservation of physical evidence and also provide a visual representation of crime scene. Taking pictures and recording videos are creating correct and detailed record of crime scene. They protect the crime scene that is found, locations of items, and potential evidence. This documentation is used as a reference for legal processes by investigators and forensic experts. Pictures and videos keep crime scenes untouched when they need to be cleaned or changed. Investigators can then refer to the images for analysis or review.

Detailed pictures and videos help forensic experts that can analyze the crime scene more effectively. Bloodstain pattern analysis and bullet path determination reviews can be done by zooming in specific areas and by improving imagery. In addition, it helps reconstruction of the crime scene and helps understand to investigators progression of the case.

Pictures and videos are used to effective visual tools in the courtroom. They help to communicate information to the judge and other interested parties by providing a clear and unbiased representation of the crime scene. By providing visual evidence, prosecutors can effectively support their arguments and better explain the case.

Starting an investigation, to provide general view of crime scene, wide-angle shots are taken to cover the entire crime scene. Detailed shots are taken including of entrances and exits. Shots should not be taken at only the eye level. Shots should be taken from a high point to cover the entire scene.

Shots of related objects or areas are taken. Shots of evidence should be taken such as fingerprints, footprints, tool marks, or bloodstains. In order to obtain high-quality imagery, appropriate lighting and equipment should be used.

Documentation of information on date, hour, and topic of each image or video record correctly is important. Related forms should be filled to provide integrity and admissibility in court of every media files. Detailed notes or explanations should be written in forms for each image or video records.

1.3 Collecting evidence

Although some biological stains are clearly visible, some of them can be hard to see due to the color of the fabric on which they are. When these two types of stains are together, this cause cross contamination [7].

In the crime scene, there are samples belonging to both victim and suspect in the course of collecting samples. For no confusion and to prevent contamination, each sample should be put in a paper bag or envelope. Samples that belong to the victim should not come into contact with those belonging to the suspect [7].

Collected materials should be recorded on both crime scene investigation report and label on the paper bag [8]. Contamination caused by physical contact can only be prevented by using different forceps and gloves; for that reason, forceps and gloves should be changed in collection of each sample.

When findings are collected, a mask should be worn and no smoking, no snacking, no sneezing, and no coughing, definitely. Attention must be paid for particles that belong to us not to contaminate the crime scene. We should not let contaminated samples with us, and we need to pay attention that our personal protective equipment is solid and complete. There is always a possibility of transmission of disease-causing microorganisms from blood and other biological fluids found in the crime scene. During the collection of cutting and piercing tools that contact blood and other body fluids such as injector, needle point, knife, and pocketknife, care must be taken not to be damaged blood and other body fluids. Overshoes worn in the crime scene should be inverted and put in the paper bag, and also, it should be noted that they belong to the crime scene investigator.

In suspicious deaths, before the victim is buried, blood, hair, or tissue samples should be taken and stored so that they can be compared with claims and findings that may arise later.

If the victim or suspect has had a blood transfusion before, the laboratory that will conduct the examination should be informed. The characteristics of the blood given or transferred to the injured victim or suspect in the hospital should be requested, and this information should be given to the relevant laboratory.

In order to make a comparison between the biological samples that are collected from the crime scene and those of the victim and suspect, blood, rooted hair, head hair sample cut from the top of the head, body hair sample if the person is bald, and buccal swap should be taken from both and should be sent to the laboratory.

1.4 Importance of packaging

In packaging of biological samples, precautions should be taken in case of tearing the package and breaking the sample, which can cause liquid samples to spill and contaminate other samples. The mouth of the paper bags should be closed with their own adhesive, and metal and rustable items such as staples should not be used to close them. Unless biological samples are stored following the rules, samples may deteriorate and lose their properties. The laboratory cannot analyze the sample that escaped the attention of the crime scene investigation team and deteriorated.

Biological samples should be stored at +4°C and in a dry environment away from moisture, and they should be sent to the laboratory as soon as possible. Temperature and humidity cause mold and bacteria to grow, and DNA will deteriorate that cannot be analyzed.

Solid items such as guns, pieces of glass, and drinking cups should be transported and protected in hard protectors that will not cause the findings to be lost, broken, or scratched.

Samples containing liquid blood, body fluids, and other infectious liquids (such as alcohol, insecticide, pesticide) and sharp-pointed substances (injector and needles used, knives) contaminated with the victim or suspect should be placed in leak-proof, unbreakable, puncture-proof, and protective covers.

2. Crime scene investigation in forensic entomology

Forensic entomology is a discipline collecting insects on corpses, studying their biology, and predicting the time of death and works for forensic sciences [9, 10, 11]. Besides prediction of death time, forensic entomology helps forensic sciences and forensic system by determining the location of death according to ecological properties of insects and whether the victim takes a narcotic or poison [12]. Although collection of insects from the crime scene is long and troublesome, it should be done definitely.

When samples are collected, temperature data of the environment and the corpse should be recorded without wasting time.

2.1 Collection of entomological specimens from crime scene

Upon arrival at the crime scene, the first step is to record your arrival time at the scene. The time period between the corpse was found and sample collection was started will be used by forensic entomologist when predicting the time of death.

2.2 Photo and video shooting

All samples collected from the crime scene should be documented before they are collected. If sample collection cannot be proved by documentary, originality of sample might be doubted. Crime scene is dynamic and complex. The slightest change can change the course of the event. Samples should be photographed and recorded as videos before they are touched, moved, or collected. Unless original positions of findings and environmental conditions are documented, any object should not be moved. Location and position of a sample and the relation of a sample with the crime scene and other existing objects should be noted to the crime scene protocol. In order to protect the crime scene, every activity should be documented, and documents should be kept very carefully. As samples are collected, materials that are under objects or the corpse will appear. When a crime scene investigator is discovered those, photos should be taken.

2.3 Temperature data

Temperature, moisture, and adequate food source are the most important elements affecting insect growth. Insects are poikilothermic species, and external temperatures directly affect the rate of enzyme activities that provide growth of the body of the insect. There exist minimum and maximum temperature thresholds in order to ensure the desired reactions and expected enzyme competencies in the insect. Other temperatures except for these thresholds can cause mortal effects on growing organism. Forensic Entomologist uses temperature data for determining the age of insects [12, 13, 14].

Ambient temperature should be measured and recorded. Weather forecast and temperature data during the period from about a week before the day the body was found should be taken from the nearest meteorological station to the scene. Comprehensive weather information including hourly temperatures, humidity, precipitation, and wind speed and direction, including current and past provinces and districts, is presented at meteorology stations.

Temperature of the corpse should be measured from the liver. If the corpse is so rotten immeasurably, skin temperature should be measured.

Measuring and recording of temperature data from larval mass, which is the intensive accumulation of larvae on the corpse, are very important data source to determine postmortem interval.

Ground temperature is measured with the thermometer touching the ground. If the area is full of leaves and branches, thermometer should be located between the branches, and temperature should be measured.

The ground temperature under the corpse should be measured by a thermometer placed between the corpse and the surface of the ground. Temperature measured from over the residue when the corpse removed can be measured slightly different due to removing corpse.

Soil temperature should be measured and recorded from under the corpse, 10 and 20 centimeters from the depth and 1–3 meters away from the corpse. When measurement is made, care should be taken not to expose the thermometer to direct sunlight.

The way a human corpse or animal carcass receives sunlight during the day should be recorded using expressions such as vertical, horizontal, in the shade, and estimating its duration.

Moisture content should be measured and recorded via either moisture meter on the thermometer or moisture meter used separately (hygrometer). The cooling of the air as a result of air movements and evaporation of moisture in the air can bring the temperature of the corpse below the ambient temperature. Those data are used by forensic entomologist in the evaluation of appropriate time intervals when estimating postmortem interval.

Move slowly to avoid disturbing winged adult flies when approaching the corpse and residue in the crime scene. Observations should be made a few steps behind to detect their activities and locations of flies (Diptera) and walking insects (Coleoptera) under the corpse, next to the corpse, and on surface of the corpse. Appropriate approaching points should be determined to provide no damage to entomological specimens.

During investigation of a crime scene including entomological specimens, it is important to use the spiral (circular) method.

In spiral method, start from periphery of the corpse and move on an ever-widening spiral plane. Investigation should be done walking from the center to the edge or from the edge to the center as the starting point. It should be kept in mind that entomological samples can be spread out 5–6 meters away from the corpse. In the situations that the boundary of the crime scene has expanded, it is extremely important that no section is left uninvestigated and that no material evidence remains at the crime scene. During the investigation, experts in the investigation team working closely with each other is very important [15].

While dissecting the corpse, especially mouth; nostrils; ear canal; eye edges and inner parts of the eyes; palms; genital apertures; folds of clothes; also, wounds, if any; the armpits; under the breasts in women; under the testicles in men; and insides of the shoes and socks should be carefully examined. Eggs and first instar larvae, which cannot be noticed at the first sight, can be seen as a result of a careful examination. Starting from the tallest, larvae and larval skins should be collected from the corpse. The larvae molt as they undergo metamorphosis. Those residues are slightly visible on the corpse, but they should be examined carefully and should be collected. Third instar larvae (L3) start migrating just before stationary period, which is the pre-pupal stage, and feeding stops. The aim of this migration is to pass the pre-pupal and pupal stages in a protected area away from outside dangers. Insects in migrate stage will hide outdoors, under the soil, between leaves and grasses, and stones under and around. At home, they will enter the pupa stage by hiding under and in the folds of carpets, sofa cushions, curtains, inside and between clothes, papers on the table, between the table and its cover, inside the air conditioner, in the ventilation holes, in front of the window, between the skirting boards.

Fly pupae are small, brown or black, and cylindrical shaped, and usually, people with insufficient experience can confuse them with plant seeds or rat droppings. While rat droppings are close to black color, small, and with an unlined structure, fly pupae have segmentation lines. The probability of unexperienced investigators missing the pupae is very high. Pupae or larvae can jam in recesses on the soles of shoes or boots.

Sample collection, photographing, and video recording should continue during the removal of the body from the crime scene to the morgue. At this time, the temperature between the corpse and the soil should be taken urgently with the help of a thermometer. During the removal of the corpse, entomological specimens will escape very quickly either into the corpse or into the soil. Therefore, they must be collected immediately. The light and temperature change because of removal of the corpse disturbs them. For this reason, the number of investigators at the crime scene should be at least two and at most three. After the body is removed, if the ground is sandy or an area that can be excavated, such as soil, samples are collected from within 10 cm and 30 cm of the soil and further below, if necessary, in order to reach the species that have entered the soil to enter the pupal stage [15, 16]. Larvae or pupae collected from under the corpse and underground will give information about the insect fauna on the corpse. Approximately 6 m of the area where the body was found should be scanned, and the found samples should be collected. However, this process should be done with a predetermined strategy, and the relationship of the corpse with the environment should be recorded by taking photographs and videos. It is very important to take pictures of the general view of the corpse, the regions with entomological specimens from different angles, and video recordings for subsequent investigations.

The photographs taken will be used by different units such as crime scene investigation, defense authority, and the prosecutor’s office. It is necessary to take photos from many angles and send them on CD to the relevant places. Because it is possible that the details become invisible due to the bending of the photo cards during the examinations or by being affected by the moisture and oil contaminated by the hand. After these processes are completed, the collection process can be started.

First, while collecting insects on or around the corpse, other objects in the crime scene should not be damaged. Otherwise, artificial damages created by people at the scene after death may mislead the event.

2.4 Entomological specimens of four different periods are collected on and around the corpse: Egg, larva, pupa and adult

Collection of Eggs: Soft forceps and plastic spoons should be used to avoid damage during collection. With the help of a watercolor brush, the samples are taken to a spoon or a tube containing 95% ethyl alcohol. Some of the eggs should be placed on a piece of liver and sent to the laboratory in ventilated containers.

Collection of Larvae: If possible, at least 60 larvae from different species and from each stage, starting from the largest larvae, and if there are enough, much more should be collected. After the larvae are killed in hot water of 85°C, they should be stored in 95% ethanol [17]. Larvae should not be placed in 70% alcohol. When the water entering the body of the larvae dying in hot water enters into the alcohol, the water in the larvae passes into the alcohol, and the alcohol is diluted (osmosis). In this case, since the 70% alcohol used will become more diluted, the larvae begin to darken and rot. Morphological diagnosis becomes impossible. Some of the larvae should also be collected and must be delivered to the laboratory alive. For entomotoxicological examinations, samples from each stage of the larvae should be collected and frozen at −20°C and sent to the laboratory. Specimens should remain frozen until identified.

Larvae to be kept alive should be placed in a ventilated box with a piece of beef liver or chicken liver or cat food, or in a glass jar with holes in the lid of which the larvae cannot escape.

Labels containing the date, time, case number, place of collection, body region, sample type, number of samples, and the name of the person collecting the samples should be affixed to the containers or tubes in which the samples are placed.

Labels affixed on the tube should be written with a pencil. A ballpoint pen should not be used as the alcohol in the tube may cause the ink on the label to be erased [17, 18]. Labels should always be prepared in pairs, with and without adhesive, and the same information should be written on both. The adhesive one should be placed on top of the sample bottle, and the nonadhesive one should be placed in alcohol in which the insect samples were placed. The double label method is standard practice in entomology. With this method, even if the label on the outer surface is dropped or deleted, it prevents data from being lost. While working, the inner label placed in the container under examination will remain inside even if some of the samples in the bottle are taken and examined, and the remaining samples remain labeled.

Coleopter larvae should be stored and transported in the same way but should not be transported alive in the same container as they are predators of fly larvae. After the corpse is removed, the larvae and pupae under the soil should be collected.

Collection of Pupae: Considering that they can be confused with stones and seeds, especially if they are on the soil, they should be carefully collected and transported in containers containing sawdust, sand, or soil. Pupae and their empty shells can remain in nature and in the laboratory for years. Therefore, drug residues are also found in the pupae and shells. If they are present at the scene, they must be collected.

Collection of Adults: Adult dipters found on the corpse or at the crime scene should be caught with the help of traps. The most troublesome aspect of catching adult insects on a corpse with insect catcher is that the activity of the catcher disturbs the fauna on the corpse and affects the presence of winged and wingless insects. Therefore, the use of succulent traps is the most appropriate method.

Coleoptera species can be caught by holding them with suitable soft forceps. In some cases, it is best to catch the adult beetles that have escaped from the forceps by hand, but it is important not to over-squeeze and cause the insect to disintegrate. Small scoops can be used for aquatic species.

Soil samples should be collected from the bottom; right and left sides of the corpse; the top, if any; and 1 meter away, and each sample should be labeled in glass or plastic ventilated containers, indicating the place where it was taken.

2.5 Sending samples to the laboratory

Some of the captured samples should be sent to the laboratory alive, and some of them should be killed. All entomological and ecological specimens from the crime scene should be recorded on the Crime Scene Investigation Form.

Each of the insects to be kept alive should be placed in separate glass tubes, glass jars, or plastic sampling containers. For living specimens to be fed, the palm size (100 g) of meat should be placed in the containers. This meat is preferably taken to the scene, chicken livers, which are easy and cheap to use, and canned cat food are more convenient. Approximately 10 insects are placed in each sample container with meat. Putting more insects causes the insects to harm each other. Sample containers should not be too narrow. In order to the coleopters to climb, filter paper or small pieces of moisture-absorbing paper should be crumpled into the sample containers.

The width of the containers is important for winged creatures to fly. In narrow containers, insects can damage themselves and lose their diagnostic criteria. Some of the flies are predators of each other. Considering this situation, a maximum of 10 live flies should be put together. Filter paper or small pieces of moisture-absorbing paper should be crumpled and put into the sample container so that they can move freely in the sample container and that diagnostic criteria such as wings and legs do not break.

3. Collection of entomotoxicologic findings

In deaths due to intentional or accidental ingestion of narcotic substances, the type and amount of the chemical that caused the death should be determined. In cases where it is not possible to analyze traditional sources such as blood, urine, and internal organs, which are used for forensic research due to decomposition in the body after death, tissues such as hair, body hair, bone marrow, and, if these cannot be obtained, necrophage insects are reliable materials for toxicological analysis. The tissue of insects and larvae to be used in toxicological analyzes should either be crushed until homogeneous in the tube or be homogenized by breaking up with a device called a homogenizer. Due to the structure of their body tissues, larvae and adults are easily homogenized and can be easily used in toxicological analyzes [19].

The crime scene should be well analyzed. Serum hose, tourniquet rubber, spoon, pipette, rolled paper, cardboard, syringe, syringe needle, needle cap, powdered narcotic substance, bags and boxes where narcotic substance is stored, packaging papers, pesticide, insecticide bottles, food scraps seen at the crime scene, empty ampoules, medicine and medicine boxes should be collected.

The most important points to be considered in collecting the findings from the crime scene are as follows:

Before the samples are collected, their photographs must be taken, and it must be documented that they are at the scene. An undocumented example may appear suspicious. Relationships with other objects should be noted and documented by photographing. The photographs taken should be of a quality and order that can reflect the scene and the event.

Care should be taken not to lose drug residues and DNA material on the collected materials.

Every material taken from the scene must be individually packaged and labeled. The name of the substance, the name of the deceased, the autopsy number, the name and surname of the person taking the sample, and the date of collection should be written on the label. Cross contamination should not be allowed. It should be transferred to the laboratory in such a way that mold and bacteria do not form. Packing the samples properly and duly will prevent the integrity of the packages from being compromised. During packaging, the mouth of the paper bags should be closed with the bag’s own adhesive, not with pins, paper clips, and staples.

The transfer of samples to the laboratory should be done without breaking the cold chain. The safety-surveillance chain means preserving samples’ journey and documenting. The name of the person from whom the sample was taken, the name and surname of each person making the transfer, the name of the organization, the storage conditions of the sample, the dates and time of collection and transfer, the sample number, brief information about the sample, and information showing the status of the seal should be recorded on the document used for documentation. A deficiency in the safety chain of custody can result in analysis results being challenged in court.

None of the solid or liquid drugs should be delivered to the laboratory without being placed in preservatives. Preservatives may cause the method of toxicological tests to be changed or result in incorrect results. There is nothing the toxicologist can do about it.

In order to prevent deterioration of the findings collected in humid and hot environments, they should be allowed to dry first and transferred to laboratories with a cold chain (+4°C).

If there is vomit or leftover food in the environment, these should also be collected and transferred to the laboratory without spoiling.

Entomological specimens should not be smelled or tasted.

While collecting the samples, dirty gloves and overshoes should be changed, and contamination of other samples should be prevented.

Do not vomit, cough, or sneeze on samples.

On-scene alcohol bottles, broken glass or bottles, ampoules, broken ampoule fragments, medicine bottles, and used needles should be transported in sealed, puncture, and friction-resistant hard cardboard or wooden boxes. Broken parts should be packed in such a way that they are not lost.

If there is blood or blood stain at the crime scene, liquid blood should be taken into tubes with the help of Pasteur pipettes; a swab should be taken with a sampling stick and labeled. Biological samples should be taken in the form of swab, either by scraping the dried blood stains or by soaking the sample stick with saline.

Soil samples must be taken from the scene. As the corpse decomposes, body fluids pass into the soil. If there is narcotic substance or toxic substance in the body of the deceased, these substances are also found in the soil.

The desire of the perpetrator to get rid of the corpse in a hurry and excitement to leave the scene causes suspect’s mistake and to leave particles from the suspect himself/herself. The performance of the crime scene investigator at the crime scene will ensure that the incident is resolved smoothly from the crime scene to the laboratory to the court.

4. Conclusion

A person committing murder is excited, anxious, and annoyed. He/she leaves hair, semen, urine, fingerprint, medicine, button of his/her clothes, bloodstain even if he/she cleans the crime scene, and such to the crime scene. Besides, he/she takes fibers of carpets, fabric, and curtain and insect, bloodstain belonging to victim, and pollen from the crime scene. Crime scene investigators are knowledge workers who work with minimum information and maximum pressure in the crime scene. They must know “how crime scene data are converted to information and to business intelligence.” This profession, which is irreversible, is the first step of providing justice. It does not accept missing or wrong sample collection. Sometimes, crime scene investigators might have to work in the crime scene. They make a big effort to understand criminal behavior of the suspect and to send materials correctly collected and packed that forensic scientists can examine and solve. The correct execution of the above-mentioned tasks is an event that affects everyone, from the police to the judge, in identifying and apprehending the suspect.

Conflict of interest

The authors declare no conflict of interest.