Alternative light sources and AFIS help identify murder suspects

Alternative light sources and AFIS help identify murder suspects

Posted on: Nov 07, 2018

Alternative light sources and AFIS help identify murder suspects

A motel room in Indian River County, Florida was about to become the scene of a homicide.

The county is north of Miami, on the Atlantic Ocean side of the state. It’s home to about 200,000 people.

A big drug deal was about to go down. One man was waiting with a stash of cocaine. Two alleged buyers came into the room, but the pair didn’t intend to buy the drugs. They were there to rip-off the seller.

The two buyers allegedly killed the suspected drug dealer, took the cocaine and escaped the scene.

The police had no initial evidence pointing to suspects.

But a fingerprint on a cocaine spoon and DNA on a drinking cup led police back to the accused. Forensic light sources helped police identify both pieces of evidence. Questioning of the suspects corroborated the story and police made the arrests.

The Indian River Sheriff’s Department in Vero Beach uses alternate forensic light sources for their investigations every day. These are light-producing handheld and lab-housed forensic instruments. The devises emit light at various wavelengths and make evidence visible that might not otherwise be seen by the naked eye. Evidence like blood, other bodily fluids, gunshot residue, fingerprints and other substances.

Investigators search for trace evidence with the instruments tuned to specific frequencies that allow certain substances to become visible.

“These are our workhorses,” Detective Sgt. Kyle King said. “They touch on a lot of cases. We take them for granted.”

Detective Sgt. Kyle King of the Indian River Sheriff’s Department

The department uses instruments made by SPEX Forensics, a division of HORIBA Scientific.

The department’s newest addition is a HandScope LED. It’s a multi-wavelength forensic light source. The HandScope LED provides more light and allows investigators to document evidence at crime scenes more efficiently with higher quality photography.

The department’s most common application when it comes to alternate light sources and fieldwork is in sexual assault cases. Bodily fluids are best visualized through alternate light sources at the scene of the alleged crime, where it exists in its native environment. That’s preferable to just bringing the specimen back to the lab, King said.

There have been a number of these cases. It’s unfortunately become a common occurrence.

The Indian River Sheriff’s Department also uses the SPEX Forensics PrintQuest AFIS (Automated Fingerpint/Palmprint Identification System) to catch bad guys.

The system catalogs fingerprints identified at crime scenes with the alternative light sources. It stores the information in a database. That in turn allows an examiner to compare a fingerprint to those in a database that’s grown into thousands of images. The database contains the fingerprints of all suspects booked into the Indian River law enforcement system.

That system helped identify the drug murder suspects. But a human touch was needed.

“It gives us more than one candidate,” Kelly Hare said of the automated system. Hare is a crime scene technician and latent print examiner with the department.

Crime Scene Technician and Latent Print Examiner Kelly Hare of the of the Indian River Sheriff's Department

“It narrows it down to a number of matches. It’s up to me to make the positive identification. I inspect it visually. I average over 300 cases a year, and have been here for nearly seven years,” Hare said.

“We make identifications fairly regularly,” she said. “I use it on all our homicide cases. It’s one small piece of the puzzle.”

Fingerprint evidence sometimes corroborates or disproves people’s statements, King said. Like in the drug rip-off homicide, police use fingerprint and DNA evidence to corroborate the suspects’ statements.

An Image from the SPEX Forensics database showing the latent print on the left hand side and the known print of the identified candidate on the right.

The drug possession identification was made by a partial latent fingerprint on the spoon.

King said his department’s alternative light sources touch almost every case they work. And a significant number of cases turn to the PrintQuest AFIS fingerprint database.

Although the light sources are used for a broad range of substances, the most common is enhancing fingerprints, using it to develop the maximum detail possible.

“We also have a variety of portable (alternative light source) flashlights, which are hand-held and battery powered,” King said. “Each of our crime scene investigators have a few of different wavelengths. For me, what brings us to SPEX Forensics is it works. The technology is durable and we don’t have any issues with it. When I flip the switch, it works.”