There are two types of strangulation. One is manual, using the fingers, another body part or an object such as a baton. The other is via ligature, which means using a rope, cord, scarf, really anything that can be used for tying or binding.
Strangulation as cause of death shows itself in many ways, the obvious being bruising and ligature marks, but also manifesting as damage to the larynx, the hyoid bone (between chin and thyroid cartilage) and other neck bones.
Investigators faced with a possible murder will know not to rely solely on ligature impressions to determine strangulation as these telltale marks can be made by similar means after death. They’ll look for additional evidence of asphyxiation and other clues the body can provide as well as circumstantial and, preferably, direct evidence.
Ligature strangulation is often the case in homicides but also occurs in accidents and suicides. One way of differentiating it from death by hanging is that the mark will most likely be lower on the decedant’s neck. A ligature mark may not be present if a soft material is used, making it more difficult to determine if the death is a crime.
In this scene from VULNERABLE, Medical Examiner Dr. Miriam Heller walks Detectives Jake Bishop and Rick Morgan through her assessment of the visible marks on the body of victim Elisa Spence.
Dr. Heller moved to the body’s feet and uncovered them. Decomposition had discolored the soles and shrunk the skin around the toes’ cuticles, giving the impression that the nails had grown.
The doctor turned the ankle so that the heel was in plain view. “She has fresh blisters and abrasions. I took a look at her remaining shoe before I sent it to the lab and noted it was older, well worn. I wouldn’t think the shoes would have worn blisters unless she’d been on her feet a long time. There are also scratches on her upper arm that suggest she ran into something abrasive like a tree.”
Jake rested his hands on his belt. “Like someone was chasing her through heavy brush?”
“That would be my guess. Her shoes created the blisters and the branches scratched her face.” Dr. Heller arched a brow.
“One could assume she lost her other shoe while she running.”
“Scent dogs are combing the brush, but so far have not found it,” Rick said.
She moved to the head of the table and uncovered the girl’s face, also darkened and drawn from death. Her lips were pale, bloodless, and more scratches raked across the left side of her face. A purple ligature mark ringed the skin around her neck like a Victorian choker. “The scratches on her cheekbones are also consistent with running through the woods.” She lifted the head and turned it to the right, exposing the flesh under the left ear. “What does that look like to you?”
Jake leaned in to study the blue-purple marks. “Looks like bruises.”
“She’s got matching sets on the other side. The shape is consistent with fingers. Because they’re in slightly different positions, it appears whoever strangled her put hands on her neck several times.”
“Strangled her but didn’t kill her,” Jake said.
“That’s right. I’ve seen bodies marked like this before. They often indicate a choking game.”
Rick pointed to the narrow ribbon of bruises around her neck. “That’s a ligature mark if I’m not mistaken?”
“It is. She died from asphyxiation. The other marks might have been enough to make her pass out but not sufficient to cause death.”
Jake flexed his fingers. “So this started as a game?”
Absently, Dr. Heller laid a hand on the victim’s shoulder. “Smart girls can make stupid choices sometimes. And she might have gone into the woods thinking it was going to be fun when the killer had a different plan all along.”
“Shit,” Jake muttered, thinking about the cave and the candle that had burned through. The killer had not simply dragged her to the cave and killed her, he kept her there for hours and toyed with her. “Any older bruises that might suggest she tried this kind of thing before?”
“No, also no signs of drug abuse. This could have been her first foray into this kind of sexual play.”
“According to her roommate she was smart,” Rick said. “But she did like to party.”
Dr. Heller raised the victim’s right hand and fanned the pale fingers painted in purple chipped at the fingertips. “Debbie found dirt under her nails as if she’d been digging. Maybe she got away and tried to hide. Also embedded in the dirt under her nails, I found skin, so I did scrapings. We’ve processed and sent it off for DNA testing. Looks like she was able to scratch him perhaps a couple of times.”
“Hopefully, she marked him up good,” Rick said.
“Be interesting to know if our killer is in a DNA database.”
“Wouldn’t that be nice.” DNA in a database wasn’t a given. If this guy had never been arrested, it was very possible law enforcement possessed no record of him.
When the heart stops pumping the blood goes to the lowest points in the body and creates an unnatural coloring of the skin. This phenomenon is called lividity.
This discoloration of the skin after death can offer invaluable clues to the investigators. For instance, if a person dies sitting in a chair or hanging from a noose, the bruising will occur in the dead person’s feet and hands. Or if the person dies lying down, the patterns will appear on the underside of the victim’s legs, arms and back. If the person is lying face down when death occurs, the bruising will be found on the front of the body. If the body’s position at the crime scene does not match these discoloration patterns, investigators have forensic evidence to suggest that the body has been moved.
So if a forensic investigator finds a body face down but the discoloration is on the back, he/she knows the killer altered the original crime scene.
Here’s Georgia at work in VULNERABLE, assessing a victim.
Georgia sat cross-legged as she lifted the victim’s cold and badly swollen hand. Though the cuticles had receded, she could see that in life the victim kept them neatly filed and painted with a faint sheen of purple nail polish that still caught the light.
Carefully, Georgia inspected the fingernails, crusted with dirt, searching for any sign that the victim might have scratched her attacker. Knowing the medical examiner would do scrapings under the fingernails, she covered both hands with paper bags. Porous, the paper allowed air to circulate so that moisture didn’t form and destroy any DNA that might be present.
“Let’s hope you scratched the hell out of him. Maybe together, we can put this asshole away.”
When both hands and feet were bagged, she gently rolled the body on its side. Pushing up the shirt, she noted a purplish discoloration darkening the backside of the girl’s legs and arms.
Called lividity, the color change was caused by blood settling or pooling in the body’s lowest point when the heart stopped pumping. Forensic technicians used stippling patterns to determine if the body had been moved or repositioned.
If there’d been discoloration on the front of the body, she’d have known the girl lay face down for a time before being placed on her back. In this case, it ran the back length of the girl’s body. This suggested the girl was positioned here at the time of death.
“A forensic light source is a crime scene investigator’s and lab technician’s tool for enhancing observation, photography and collection of evidence including latent fingerprints, body fluids, hair and fibers, bruises, bite marks, wound patterns, shoe and foot imprints, gun shot residues, drug traces, questioned documents, bone fragment detection, etc.” *
As noted in the description above from Horiba Scientific, the right tools—in this case proper or specialized lighting—for examining potential evidence is invaluable. That coupled with thorough and painstaking attention to detail Georgia-style can make all the difference in finding and convicting a felon. In this excerpt from VULNERABLE she uses white light while combing for evidence and black light to identify blood stains.
Pushing him from her thoughts, she focused on the white striped button-down shirt, taking extra care to tug any wrinkles on the arms or front panel. She clicked on a light suspended from a retractable arm and shone it on the material. She would go over the shirt, combing the fibers and threads for any loose materials that could be tested for DNA.
Killers always thought they were clever, but like she had said before, they all left something behind for her to find. It might be barely noticeable, but it was there.
She moved up and down the shirt, plucking several dark hairs with tweezers and then bagging and tagging them. She collected blood samples from the torn right sleeve and from the collar of the shirt. Once she reviewed every inch of the shirt a second time, she turned off the white light and grabbed a black light. Clicking it on, she scanned the shirt, searching for stains, including blood, semen, or urine. As she raised the bottom hem of the shirt, she spotted a faint stain glowing under the black light.
“Hey, now,” she muttered. “Where did you come from?” She carefully clipped away part of the fabric and dropped it in a test tube. “Thought you were so clever, didn’t you.”
“Did you say something?” Brad asked.
“Found a stain.”
He raised his head. “Good.”
Georgia scraped dirt from the bottom of Elisa’s shoe, plucked hair fibers from her skirt and documented two more stains.
She studied the shoe Elisa had worn into the woods. It was simple but expensive. Checking the label on her skirt and shirt, Georgia noted the moderately priced labels.
“The bodies in the back chamber look like a murder suicide,” Brad said.
“I’d have bought it, if not for the newest victim. No way a second killer would have found that cave. No way.”
Likely little forensic data remained on the bones, but it only took a little to connect killer to victim.
Amido black dye is a sensitive protein stain that is suitable for collecting latent prints on blood stained surfaces. Whereas another agent may rinse away (on tile) or destroy (on paper) the bloody finger print, Amido black dye bonds to the proteins left behind by a finger and then affixes it to its surface.
A quick, strong contrasting process, the stain will color the protein a blue-black color. And as you can see, we found protein left behind by a finger writing ‘hi’ on a piece of paper. Though we developed our proteins in solution baths, Amido black dye can also be put in a spray bottle for use at crime scenes.
VCU Forensic Fact #3: Bloodstain Patterns–How the Blood was Shed
Using physics, biology and mathematics, an investigator can study a bloodstain’s pattern, size, shape, location and distribution to determine what either shed the blood or what might have come in contact with it. Blood spatter patterns, transfers, and voids can help investigators recreate the sequence of events before, during and after the crime. To do this, investigators must match blood patterns to the objects that created them.
At VCU we we played a guessing ‘game’–match the blood pattern to the object. Some patterns were easy to match whereas other we quite a challenge.
Below we are identifying the object that created the bloodstain pattern.
A chip of paint can be an important source of trace evidence that helps investigators solve a crime such as a hit and run accident or a breaking and entering. Paint chips and flakes knocked off of a vehicle during a collision can help pinpoint a vehicle’s make, model and sometimes the year.
Paint can also identify a tool used to wedge open a door or window during a burglary. It is often the under layer of paint that provides the most information to an investigator.
Because paint is on most surfaces, it is a valuable source of evidence.