jimtrue.com : school : CJT1111 : 2003-07-30: Homicide Investigation
Posted by Jim True on July 30, 2003 6:52 AM. Last Updated October 22, 2006 9:23 PM
Disclaimer for all material noted here is at the bottom of this web page.
2003-07-30: Homicide Investigation
Professional Investigators: When you figure out what happened at your crime scene, it will tell you 'why' it happened, and once you know what and why, you'll be figure out 'who did it'.
Serial Killers are a little bit different; they get into it. Rapes and sexual assaults and serial killings were about 'power'.
Methods of Operation: often did not start right out with their MO right at the start; once they figured out their MO, they became better at it.
Video: Blood Trails (Medical Detectives - The Blood Trail)
1984, Portsmouth. Graham Backhouse. Neighbor Bedale Taylor arguing over a land dispute. Bedale Taylor dead by gunshot. Backhouse cut on the face and chest.
Blood trails incorrect; no blood in the hallway, no blood on the gun, no signs of a struggle. All blood drops were 90 degree blood drops as if the victim was standing. No void inside the bloody palm. No defensive injuries. Notepad with circular doodle that matched the impression on the 'You next' note.
Rigor Mortis - Stiffening
Livor Mortis - Coloring (Lividity)
Algor Mortis - Cooling
Blood will settle in 8-10 hours. Reddish purple. Fixed in 8-12 hours.
Rapid cooling, snow or water will affect lividity.
If there is pressure against the skin, blood can't settle into that area; blanching or bleaching, areas where lividity is absent. Restrictions will cause it to settle at the last point it can reach.
Hanging will always create a 'v-pattern' where the rope was high. Otherwise he was probably choked.
Lividity and brusing will be hard to determine; Medical examiner will have to determine. No blood in the fatty tissue; it is not bruising.
Cooling, factors: very fat, slowly, child, much faster. Immersion in water (cools you down 10 times faster).
Mummification, like hard dry, brittle leather. Hot room, no moisture. Mummify.
First part of the body that starts to deteriorate is the stomach, due to the bacteria always present in the stomach. Will also start to bloat, due to the gases in the body. Marbling is the blood veins visible through the skin.
Just the opposite when in the water or wet area. Skin slips, Adipocere, all like a soapy, fatty wax. Adipocere, all the organs become the same color; can't tell where the different organs separate.
Positional asphyxiation: get drunk, slide down and suffocate. The position you are in will kill you. Often see this in auto accidents, they are alive, but they are crushed by something so they can't breathe.
AutoErotic Asphyxiation. Slip cord they can pull to release the noose. Parents and relatives will want this written up as a suicide. This is considered accidental death.
Choking out causes 'petechia' in the eyes.
Contusion - cannot fit a door knob inside the bone socket of the eye. Bruise inside the eye pattern, person was punched.
Contusions, brusing.
Laceration, looks like a cut, blunt force hit and cut the skin. Bridging occurs where tissue still connects across the gap of the laceration. With cutting the bridging will not occur.
Butt of the shotgun is curved, smooth lacerations.
Defensive wounds from the elbow down to the hands, 95% of the time defensive or self-inflicted.
Land on your feet, the long bones come through the bottom of the leg, when falling.
For suicide, you must prove intent that the person intended to commit suicide. Prior attempt marks.
Blunt force, hits you, punches you or if you are traveling and strike something or fall. Person might die in a car accident from blunt force trauma of the brain slamming around inside the skull and bleeding internally from blunt force trauma.
Hit and run, bumper bruises at the knee level.
Cutting stabbing and chopping (not to be confused with bruising, abrasions or lacerations).
Cutting is longer than it is deep (incised); stabbing is deeper than it is long. single bladed (steak knifes). Hunting knife or bayonet type knife, both sides sharp (double-edged knives).
The muscular structure of the body will affect the stab wound. Muscles will pull the stab apart, depending on the direction of the stub or cut on the body.
Short shallow incisions. Rapists will typically threaten to cut the woman's face up.
Bombing or explosion deaths; arms, legs and center or the torso.
Flash of electricity (high voltage, arcing).
Firearms - Contact, Midrange and Distance shots.
Projectile, burning powder and soot.
Tatooing on distant shots.
Contact shots, gases inserted into the body. Abraded seared margin. Classic star pattern.
Not soot, only tatooing, distance shot. Projectile won't always kill; bone fragments will kill.
Usually exit wound is bigger than the entrance, but not always the case.
*Pyramid of Homicide Investigation (Bottom to Top)*
# Discovery of Crime
# Primary Crime Scene
# Secondary Crime Scene (suspect, clothing, body)
# Post Scene (Office, Lab, Autopsy)
# Investigative Stage
# Identity & Arrest (of Guilty)
# Case Preparation (preparing trial of prosecutor)
# Prosecution (trial)
*3 Things that Solve Homicides (Crimes):*
# Witness Statements
# Confessions
# Physical Evidence
_Of Course, the first two are OFTEN useless_
Death by Fire (or when Fire is usually inevitable); rule of 9's. As soon as you hit 18%, the person is probably going to die as it's too much of a shock to the body.
* Head is 9%
* Each Arm is 9%
* Each Leg is 18%
* Chest, Stomach, Abdominals 18%
* Back 18%
1800 Degrees, Typical House Fire. Even in half an hour, the body will not completely burn; you will still find a body. The hands and feet will be gone, but there is still too much water in the body to burn completely.
Even in a Crematorium, where the temperature will rise to 2500 degrees, there will still be bones and teeth that have to be ground down to powder.
*Drownings* -- No _one_ test can determine drowning as the cause of death; _Entire Investigation_ is used to determine drowning, and even then it is only considered an "association of evidence".
*Choking* -- Hyoid bone broke, the person is choked.
4 lbs of pressure on the veins to stop blood flow *from* the brain (Sleeper Hold).
12 lbs of pressure on the arteries to stop blood flow *to* the brain.
2-12 minutes before unconsciousness.
30 lbs of pressure to break the hyoid bone and stop the air flow.
Hanging, strangulation from a fixed point.
Strangulation, compression of the neck without suspension.
Throttling, strangulation with hands
Arm throttling, yoking
Rope/Ligature, garroting
Photo, Video, ALS, Photo, Measure, Collect, Protect - Evidence Process.
CAP Kit - Crime Against Persons
Disclaimer: These are MY notes taken from classroom lectures while I'm in the classroom. While I'm perfectly happy to share my notes with my classmates and I know I take very good notes, you should still make every effort to attend the class and TAKE YOUR OWN NOTES. I will not transcribe everything the instructor says in the classroom, and I will NEVER post pre-exam reviews. My notes will not replace the value of actually attending class and taking your own class notes.I also cannot attest to their accuracy, other than they are what was provided in the lecture; you should not reference my notes as "expert opionion" by any means, and if you notice an error or omission, please do me the favor of e-mailing me with the correction and I will re-post my notes. End of Disclaimer.