Hair at The Crime Scene

Hair recovered at a crime scene can be valuable to forensic scientists Hair recovered at a crime scene can be valuable to forensic scientists. Crime scene technicians collect any hairs that they find and send them to the lab for analysis. Forensic scientists are familiar with hair structure and chemistry.  

A hair is composed of three distinct layers - the cuticle, cortex, and medulla. The medulla is made of cells that run through the center like a canal but it may not be a continuous canal - it can be interrupted, fragmented, or absent.

Forensic scientists first determine if a hair found at a crime scene is a human or an animal hair. If it is human, they compare it with the hairs of suspects to see if they can make a match. If it is an animal, they can often identify the animal species.

Hair found at the crime scene Hair found at the crime scene. When viewed through a microscope the crime scene hair looks like this: What kind of hair is this - human or other? What are the implications and possibilities that this clue could lead to?

Cat!

Matching human hairs

Naturally shed hairs, such as a head hair dislodged through combing, display undamaged, club-shaped roots.

A hair forcibly removed from the scalp will exhibit stretching and damage to the root area.

Forcibly removed hairs may have tissue attached.

Body hair: Hairs that exhibit microscopic characteristics shared by different anatomical areas are often referred to as body hairs. These include hairs found on the upper legs, lower abdomen, and back.

A razor cut hair

A split hair

A recently cut hair

A hair showing buckling

Hair from the head…

Caucasian hairs can be of fine to medium coarseness, are generally straight or wavy with colors ranging from blonde to brown to black. The hair shafts vary from round to oval in cross section and have fine to medium-sized, evenly distributed pigment granules.

Mongoloid or Asian hair is coarse, straight, and circular in cross section, with a wider diameter than the hairs of the other racial groups. The medulla is continuous and wide, and contains pigment granules that are generally larger in size than the pigment granules of Caucasian hairs.

Negroid or African hair is curly or kinky, with a flattened cross section, appearing curly, wavy, or coiled; pigment granules are larger than those found in Mongoloid and Caucasian hair and are grouped in clumps of different sizes and shapes. The hair shaft often exhibits variation or apparent variation in diameter because of its flattened nature and the manner in which it lies on the microscope slide.

When hairs originate from a body in a state of decomposition, a dark band may appear near the root of the hair. This characteristic has been labeled a postmortem root band.

Hair that has been burned

The victim in this case is Lily, the wife of a handsome industrialist who flirted (and maybe more) with five women, all of whom were madly in love with him (or maybe with his money). Each was sure that if he were not married, she would be “the one.” Lily went out riding one spring day, but her horse returned to the stables without her. Her body was found at the edge of a field. The autopsy revealed that her neck had been broken by a powerful blow with a blunt object.

Examination of the crime scene suggested a struggle Examination of the crime scene suggested a struggle. Investigators sent Lily’s clothing to the crime lab. They were especially interested in a wool sweater that yielded many hairs: a) horse, brown b) human, blond c) human, brown d) cat, gray e) cat, orange

Violet is a computer programmer who works for the Census Bureau. She has long blond hair. She enjoys sports, especially horseback riding. She rents a stall in Lily’s stable.

Daisy is a redhead who dyes her hair. It was recently cut short. She is a nurse, a bit overweight, and shares an apartment with Violet. Her cat is a thoroughbred Maine coon cat named Gloxinia. She is a member of the SPCA & has recently picketed a local store that sells fur coats. She went to high school with Lily and Camellia. http://en.wikipedia.org/wiki/Maine_Coon http://www.youtube.com/watch?v=1X-OdnRnQQw

Rose Rose is a brunette with long, curly hair. She lives with her golden retriever and keeps pretty much to herself. Rose smokes Merit brand cigarettes. She is one of Lily’s neighbors.

Iris is an outstanding softball player. She plays third base for the Diggers, a team sponsored by a local mortuary. She claims to be a natural blond and just got a haircut. She works for Lily’s husband.

Camellia is also a blond who bleaches her hair, which causes split ends. She runs 10K races throughout the year. She works as a salesperson at the local sporting goods store. It is common knowledge that Iris and Camellia do not like each other.

Drawings from the microscopic examination of the control and unknown hairs are shown below. Is there enough evidence to establish a definite connection to a suspect? If not, what more is needed?

Star known Facts in your chart Question: 1. Is more evidence needed? make up a grid showing suspects and victim versus evidence then match the known facts. Name Hair description Misc. evidence Relationship to husband Relationship to Victim (Lily) Violet Daisy Rose Iris Camellia