ALBANY (PIX11) – Cheryl Strevell has been a forensic scientist in the New York State Police crime lab for seven years now, and she’s been called on to swab a multitude of surfaces, seeking biological fluids that can help solve criminal cases.
“We’ve had a seat from a truck that we had to test,” Strevell explained. “The suspect was allegedly sexually assaulting his daughter and it was going on for years, she said. She said it occurred in the truck numerous times.”
Even though Strevell swabbed the entire seat for evidence of seminal fluids, the results turned up negative. “I even cut off the top layer of the truck seat to get into the sponge layer in the middle,” Strevell recalled. But there was still no evidence.
Strevell had more success with another, large object. ‘
“There was an alleged sexual assault that occurred on a dining room table of a young child,” the scientist told us. “So, we were searching for seminal fluids and blood on the dining room table.”
This time, the test was positive.
Strevell showed us a chemical called brentamine that she uses to find enzymes found in seminal fluids. She uses a chemical called leucomalachite to swab surfaces that may contain hemoglobin, blood.
She spends a lot of her time swabbing clothing, bedding, and weapons.
The Forensic Investigation Center in Albany is located on the State Campus, off Exit 3 on Interstate 90. It was built in 1996, and it’s home to the DNA databank, a latent fingerprint section, a firearms division, and trace evidence unit.
John Michael Egan is a senior investigator in the Latent Print section, and he told PIX 11 fingerprints are still king, when it comes to evidence.
“Your fingerprints are totally different,” Egan explained, pointing out identical twins can have the same DNA but not the same fingerprints. “So fingerprints are better than DNA, we say.”
Dr. Jill Dooley works in the trace evidence unit and showed us a footprint from a crime scene. The suspect was wearing Converse sneakers. She also showed us how she matches up a ripped carpet
pulled out of a crime scene with the rug left behind. “You can line up these two pieces, looking at the continuity and surface markings,” Dr. Dooley said.
Coming up later Thursday: how the state crime lab recreates human faces from skeletal remains, hoping to identify bodies that no one ever claimed. The images are haunting.