Baltimore has experienced its highest murder rate in history through the first four months of 2017—but authorities there are now receiving federal help in the form of a mobile gun-tracking van from the ATF, reports Forensic Magazine.

The mobile laboratory van is brand new, with its deployment in Baltimore yesterday being the first time it's been used in a major metropolitan city.

The van is part of ATF's National Integrated Ballistic Information Network (NIBIN), which provides equipment to police departments that allows them to gather critical ballistics information in a timely manner.

"[Local and state police departments] use NIBIN to input either shell casings recovered from crime scenes or test-fired crime guns that have been recovered from a crime science or off a person," ATF Special Agent David Cheplak told Forensic Magazine. "Ballistic information is gathered based on specific properties left on either the shell casings or on bullets fired from crime guns. It's almost like a fingerprint the weapon itself leaves behind."

That ballistic information is stored electronically and will initiate a "hit" when evidence from one gun crime matches new evidence being input into the system for a separate—but possibly related—crime.

Putting NIBIN on wheels allows the ATF to 1) supplement already existing equipment in a city like Baltimore, which already has the equipment and system but can always use the extra hands, and 2) bring the van to jurisdictions that don't have the technology and have not been able to use the program in the past.