Poison Analysis

A poison is defined as a substance that when introduced to a living organism, may cause harm or even death. In forensics, chemistry is often employed to analyze blood and other substances found at a crime scene, to attempt to identify any poisons that may have been part of the cause of death. Poisons may include substances such as cyanide or arsenic, which are extremely harmful to any animal, and also substances such as iodine or sugars, which may be harmful to people with specific diseases such as diabetes or thyroid problems.

Poisons can be identified in many cases with the addition of a reagent that will react with the poison, and cause a change in color,smell, or may produce a precipitate or gas.

Several samples of an unidentified poison on a petri dish, with various indicator chemicals applied.

Lipstick Analysis

In forensics, a imprint or a stain left by a person's lips may be used to assist in identification.

The above image depicts an imprint of a subject's lips, left in red lipstick. Some identifying features to this particular set of lips includes the noticeable vertical grooves in each lip, as well as the characteristic spaces between the lips, as marked in the image.


A particular experiment carried out as an exercise in applying lip-print identification skills was carried out under controlled conditions. Various lip-prints were applied to a sheet of white paper. Each individual lip-print found on the sheet were also impressed upon singular note-cards. The master print sheet was exchanged, along with the note-cards. Using these print-identification skills, prints on the master sheet were given characterizations and had their features examined closely. Following this, the note-card prints were matched with the master sheet prints, with varying degrees of success which I will not discuss in great detail here.

Crime scene analysis

At a simulated crime scene, 12 pieces of evidence were found. The simulated crime scene takes place in a suburban residence and yard, in which the house was forcibly entered. The evidence was found in the yard and home. The evidence is described below.

Exhibit 1: A black leather, high heeled shoe.

Exhibit 2: A torn up note, which read "Someone please help me!".
Handwriting matched to Tyrese Jefferson.

Exhibit 2A: A torn up note, which read "You will never find her!".
 Handwriting matched to Smokey Johnson.

Exhibit 3: A single fingerprint
Matched to Smokey Johnson

Exhibit 4: An ear ring

Exhibit 5: A scrap of green nylon fabric

Exhibit 6: A sample of clear, yellow liquid.
Tested positive for Iodine.

Exhibit 7: A footprint found in the residence's yard.
30 cm long, 10 cm wide. Diamond patterned, flat sole.
Likely made by an adult male.

Exhibit 8: A sample of A+ blood.
Matched to Tyrese Jefferson.

Exhibit 9: Dog hair

Exhibit 10: A latent fingerprint left on a piece of glass.
Ulnar loop.
Unable to match with any suspects.

The story pieced together by the evidence found at the scene is as follows.

Tyrese Jefferson, after a late night out partying, returns to her home in an inebriated state.
She begins to undress by removing one shoe. After the shoe is removed, she notices a suspicious figure approaching her home and recognizes it to be Smokey Johnson, who Tyrese Jefferson recently had a restraining order filed against. In her confused, inebriated state, she writes a note reading "Someone please help me!" and leaves it on her dresser. Johnson crosses her yard and leaves the footprint; He then forcibly enters the home and assaults Jefferson. In the struggle, Jefferson is bloodied and knocked unconscious - The single ear-ring found at the scene was also knocked off in the struggle. Johnson noticed the note left on her dresser, and rips it up. He then writes another note, reading "You will never find her!", and rips it up in a misguided attempt to confuse investigators.
He then carries the unconscious Tyrese Jefferson off into the night.


The conclusion was reached that the Dog hair and Iodine samples found were irrelevant to the investigation. Due to Jefferson's thyroid problems, she used the Iodine as a medication, and it was left open in her home after her abduction. The Dog hair was left by Tyson, a local dog who wandered inside the home after the abduction due to the front door being left open.