Anya Lester and three other Las Vegas (NV) Metropolitan Police Department forensic scientists are working around the clock to help solve crimes in bulk. They work in an office building with a laboratory and a makeshift gun range, connecting cartridge cases from impounded guns to open criminal cases, reports the Las Vegas Review-Journal. And at a time when violent crime is climbing in the Las Vegas Valley, they are working more than ever.

The cartridge cases — which are essentially a bullet's container — are filled with gunpowder, and when they're fired and ejected, the cases are marked up with a pattern unique to the gun used. The patterns are what Lester is looking for.

"This is the first time since I've been here where it's actually been one of the most popular requests that we've had," said Kim Murga, who heads the Metro laboratory where Lester works. "And DNA has taken kind of a back seat."

The technology isn't new. The sheriff's support is.

"From a strategic perspective, it gives you a more holistic perspective," said Matt McCarthy, deputy chief of Metro's investigative services, which oversees homicides and robberies. Instead of isolating an investigation to one street corner, the cartridge cases may connect crimes miles away. "It allows an investigator to ask more questions," he said.

The main tool scientists like Lester use to make these connections is a federal database, called NIBIN, or National Integrated Ballistic Information Network.

Impounded guns are fired. Ejected cartridge cases are collected, then scientists like Lester input the samples into the database. Cases from crime scenes are compared.

"It's kind of like," Murga said.

Once the system identifies possible hits, the scientists put the cartridge cases under a comparison microscope before officially determining a possible match.

"People are really excited about it because it is actually hooking these smaller crimes to larger crimes and providing leads for the investigators," Lester said.