רצח או התאבדות? פתרון תעלומה בעזרת ניסוי מדעי

Abstract

   In this paper a case of death investigation is presented. What started as a suspected suicide, of an IDF's officer shooting himself, became a case of suspected homicide. Analysis of bullets trajectories, conducting a field shooting test and determination of shooting sequence, shed some light on the mystery. 

Keywords: Bullet trajectory, Shooting sequence, Death investigation

Introduction

   Investigating a crime scene, in order to understand what happened in it, can be a very difficult task. A crime scene involving shooting is one of the most difficult to investigate, to understand and to reconstruct.

   In order to reconstruct the events in a shooting scene, the Crime Scene Investigator (CSI) needs to perceive a lot of details, many of them are obscure because the shooter tried to cover them up, or people who entered and disturbed the scene, such as firefighters or paramedics, moved the evidence or even destroyed them. Furthermore, there is a lot of "white noise" in such scenes.

    Many times it is crucial for the investigation not only to know the general events that occurred at the scene, like who shot who, but it is crucial to know the sequence of the shots: which one was the first, the second and the last.

    Not every time it is possible to find the shooting order but sometimes, like in the case presented, there are enough marks and evidences that can lead the investigator to a conclusive answer. There are many ways to reach this conclusion; in the case we describe below a two phases shooting experiment was conducted to cover all possibilities of shooting sequence in order to understand and resolve the mystery.

 Case Description

   The case started when a young army lieutenant was found dead in his car. The car's doors where closed and locked, the key was in the ignition switch, the hazard lights were flashing and the left-rear window was shattered.

   When police investigators, including CSIs, examined the scene closely, they found that the driver's seat backrest was pushed back and the deceased was laying on it with his left arm under the seat's safety belt.

   On the front passenger's seat, some personal items of the victim were found. All items were covered with the deceased's blood. His personal weapon, Colt assault rifle model M4, a short variant of Colt's M16 AR, was in a SAFE mode with a bullet in the chamber. The rifle, which was partially covered with a plastic bag of an X-Ray photo, was also heavily stained with blood.

   Blood stains, smears and drops were also found all over the inside surface of the front passenger's door and the door of the glove compartment.

   Two cartridges, of caliber 5.56X45 mm, were found on the rug, near the lower limbs of the victim. The investigators thought that the bullets went through the left-rear window but later on it was found out that only one bullet broke the window, the other bullet hit the left central pillar (or post), penetrated it and fell to the bottom of the car's chassis, were it was found in fragments.

   Examination of the deceased, revealed one bullet entry hole in the front of the left side of the uniform's shirt and another entry hole in the left arm. The first bullet went through the shirt, the undershirt, entered the left side of the chest and came out from the left side of the back, near the shoulder blade. Continuation of the bullet's trajectory showed that this bullet was the most likely one to break the window.

   The second bullet entered the inner side of the left upper arm and came out from the outer side of the left upper arm. Continuation of this bullet's trajectory showed that this bullet was the most likely one to hit the left pillar.

   Examination of the body, by the medical examiner, showed, among other things, a unique burn pattern on the left side of the chest, in the shape of "flower petals", caused by the flash suppressor of the gun. (Pic. 1)

   This pattern (Pic. 2) was later proved as a key item in the determination of the shooting sequence.

   None of the shots led to immediate death and according to the medical examiner it took the victim more than few minutes to die.

   After receiving the reports from the police CSI expert and the medical examiner, the Military Criminal Investigation Division, which was responsible for the whole investigation, concluded that the exact circumstances of the death are undetermined and they cannot have a final distinctive conclusion. The CSI's report and the medical examiner's report, however, implied that the death was self inflicted.

   At this point, the family, which refused to accept suicide as an option, turned to the authors for help.

   From close inspection of all the evidence, rose many questions which the police CSI unit and the medical examiner had no answers to:

• How did blood get to the right side of the car?
• Who put the weapon in a SAFE mode?
• Who covered it?

And the most important questions:

• What was the order of the shots?
• What were the trajectories of the two bullets?

   The answers to these questions were important because the locations of the shots were puzzling. For example, if it was a suicide and the officer shoot himself first in the arm, why did he do it? It only caused him pain and made it difficult for him to fire the second shot. On the other hand, if he shot himself first in the chest, why he placed another shot in the arm?

  The trajectory of the shot to the chest, did not coincide with the "usual" trajectory of shot to the heart, were people shoot themselves in order to commit suicide. 

   In order to receive better answers to these questions, we have decided to conduct a shooting experiment, which would hopefully provide some useful information, which in term will help us come with a definite answer.

The Test Procedure

   We took a piece of pork's hide and put it on a carton box, (which simulate the chest). Then we covered the hide with an undershirt and a shirt on top of it.

We made two rounds of shooting tests:

   On the first test, we fired the first shot at the "chest" and the second shot at the "arm". Both shots were fired in angles similar to those measured from the body of the victim.

   On the second test, we fired the first shot at the "arm" and the second shot at the "chest". Also in this round both shots were fired in angles similar to those measured from the body of the victim.

Test's results & analysis

   On the first shooting experiment, we saw that the shirt and the undershirt were torn, but we did not get the "flower petals" pattern on the skin, instead we got a single burn pattern.

   On the second shooting experiment, we also saw that the shirt and the undershirt were torn, but this time we did get the "flower petals" pattern on the skin.

  Those shooting experiments clarified that the shooting mechanism was as follows:

   On the first shot, the barrel's end was close to the chest and the shot, fired in the direction of the left upper arm and almost parallel to the chest, created a shock wave which tore the shirt and the undershirt, living the skin exposed. When the second shot was fired, this time directly to the chest, the flame burst through the flash suppressor vents, living the "flower petals" pattern.

   Knowing that the chance of someone wanting to kill himself, will first shoot himself in the arm,  - not a location with significant lethality potential, on top of causing a very painful wound, which limits the possibility to use this arm for a subsequent shot is very slim, supported the thought that it is not a suicide attempt.

Conclusions

   After getting the tests results and combining them with other evidence, out of the scope of this article, we came to a conclusion that there was a reasonable probability of involvement by another person in the death of that young officer.

   Our findings and reports were presented to the head of Investigations and Intelligence Department, in the Israeli police, and to the head JAG, in the IDF, which ordered to open the case again as suspected murder.

   This case demonstrates the importance of determining, when-ever it is possible, the shooting sequence, when someone is hit by multiple shots. It is also shows that by conducting a simple test with minimum of accessories, one can change the leading hypothesis of a case from suicide to homicide or vice versa.

Pic. 1 – Typical muzzle flash of M16 AR

Pic. 2 – Typical "flower petals" burns on skin