Thom Jones, a foresnsic science instructor, gave a presentaton at the Cornwall Public Library last week. One of the exercises was to dust for prints on a CD.
Forensic science isn’t used just to solve criminal cases; last week, about 18 children got to see how evidence is collected at a crime scene.
Thom Jones, a former attorney and now a forensic science instructor at SUNY Empire State College, visited the Cornwall Public Library, to teach the kids about fingerprints.
Each person is born with different fingerprints. It’s what makes us unique. Fingerprints are formed 10 weeks into pregnancy, which means even identical twins aren’t exactly the same.
Many factors contribute to the appearance of one’s prints including mother’s health during pregnancy, the environment, and later in life, a person’s job. As one grows, fingerprints get larger and eventually lines will form across them caused by dry skin and doing the same tasks over and over again. Certain medication could also affect one’s fingerprints.
There are three main types of fingerprints. Loops are the most common and look like bananas with a triangle underneath. Whirls are the second most common and can look like targets or spirals. The third most common are arches, looking like a little hill or a steep hill. Other types include double loop, central pocket loop, or accidental, meaning they don’t fit any pattern.
Due to their exclusivity, fingerprints are commonly used to either pinpoint a suspect or rule someone out in a crime.
Toes, ears, lips, and the tongue may also help identify a suspect, but the latter three aren’t very reliable, nor commonly found at a crime scene.
When searching for prints, Jones explained, a crime scene investigator must figure out what a criminal might touch.
A black powder is brushed onto a surface to reveal any hidden prints, which are then logged as evidence. Prints can be lifted from immovable objects by using tape.
Once a print is brought back to the lab, it’s scanned into a computer and enlarged. The fingerprint expert will then mark a certain number of distinct spots, depending on agency requirements. If one point does not match, neither does the rest of the print.
With tools of the trade spread out on a long table, Jones had the children print themselves using ink and then lightly pressing on a piece of paper. He then went around the room explaining what types of fingerprint each had.
A second exercise had the kids touch, with a finger, the oil on their faces. They then pressed that finger onto the surface of a CD. Using the dust and a brush, they gently rubbed the bristles over the CD until their fingerprint appeared.
Before the session ended, Jones explained that blood at a crime scene can also be used as evidence. It contains DNA, which is unique to individuals other than twins. Bluestar, which is used at a crime scene, merely determines if a sample collected is indeed blood because of a protein it contains. The sample needs to be taken back to a lab in order to determine who it belonged to.
Finally, Jones shared his thoughts on the O.J. Simpson murder case and why he may not have killed Nicole Brown Simpson and Ron Goldman.
Blood collected from Simpson’s vehicle contained a preservative found only in sample tubes. A glove, introduced into evidence did not have the same cuts as appeared on Simpson’s hand. During the trial, when questioned if he planted the glove, a detective pled the fifth (amendment) making him appear guilty. Finally, a bloody sock was found with stains on both sides. It would have been stained on only one side if the victim had been wearing it.
While these three pieces of evidence don’t absolve Simpson of the crime, Jones speculated the police thought he was guilty, but needed more evidence, so they planted it.