Investigative reporter James LaPorta led reporting on the latest story in AP’s ongoing investigation of missing military weapons, revealing a weapon-tracking technology that the U.S. Department of Defense itself describes as a “significant” security risk.

After showing that the military has lost track of at least 1,900 guns, AP trained its sight on how technology might help in weapons accountability. They found that one solution — putting radio frequency identification tracking tags inside guns — has introduced a security vulnerability into Army and Air Force units because it could help even relatively low-tech enemies target U.S. troops on the battlefield. The Pentagon originally appeared unaware that some units were using RFID, then said it allows service branches to explore innovative solutions. The Navy says it is halting its own program of RFID for weapons; the Marines have rejected the technology.

To demonstrate the highly technical story in understandable ways, LaPorta and editor Justin Pritchard arranged field testing that showed the tags could be tracked from much greater distances than RFID contractors acknowledge.

Photographer Noah Berger and video journalist Terence Chea illustrated the testing. Producers Serginho Roosblad and Peter Hamlin turned that material into a sharp explainer video with the help of editors Jeannie Ohm and Raghu Vadarevu. Storytelling producer Nat Castañeda curated the AWOL Weapons hub and worked with Patrick Sison for the photo edit. Kristin Hall in Nashville contributed important reporting.