Obtaining a biometric record on a suspect to match against a terrorist video of a masked jihadi is not something done easily or robotically. It requires old school investigation, either sifting through lots of hours of collected video footage and comparing that to crime videos (such as beheadings), or going out into the field to find voice samples on suspects to match against crime videos, or both.

This is where the Defense Department’s extensive library of biometric signatures, gathered on the field in places like Iraq and Afghanistan, can play a role in future investigations. The department’s biometrically enabled watch list, or BEWL, houses more than 200,000 records.

“I can’t speak enough about our relationship with the Department of Defense. After 9/11, our mission in life changed. It was all about national security, our partnership with DHS and DOD -- to say it expanded is an understatement,” Morris said at a recent biometrics conference in Washington, D.C. “Their ABIS system was connected with our system, so they have a small group of folks who are out there [in West Virginia] in charge of their system. Having them co-locate with us has been very important.”

That important relationship is about to get a lot more intimate. Later this year, the FBI is going to open a $328 million, 360,000-square foot Biometric Technology Center next to the current CJIS campus. The Defense Department will get about 40,000 square feet in the building, which will also consolidate the FBI's biometric workers and operations. “Anything and everything we do will be run out of that building,” said Morris.

In September of last year, the FBI announced that the $1.2 billion dollar NGI system was fully operational (it was rolled out in increments over a period of years). If it works according to plan, it will provide law enforcement with a very fast and reliable sense of exactly who they are talking to, what threat that individual may pose, and what records they’ve left -- fingerprints, voiceprints, etc. -- in what places.

But fingerprints don’t help you catch everyone. Voice recognition played a key role in the identification of Jihadi John, according to published reports. The FBI’s biometric center site lists voice recognition as one of its key modalities, or areas of study, along with DNA and others, but fingerprints and more traditional biometric signatures make up a bulk of the records it manages.

Voice, in many ways, represents a crucial gap in biometrics collection for both the Defense Department and law enforcement. In a noisy environment it can be very hard to get a dataset to do matching against, a huge technical issue that the government is actively looking to solve .

In Iraq and Afghanistan, soldiers have compiled huge datasets of people that they have come across, including finger scans, pictures, and iris scans. Any of those can serve as a reliable red flag for a Turkish border guard, or, for that matter, a New York cop with a suspect in the chair. But they don’t do much against a villain broadcasting terror from a safely fortified mountaintop in Syria.

Some of the men fighting with ISIS today have probably left their fingerprints in a few places where Western law enforcement could pick them up and share them. Technology, by itself, won’t find those places. But, once the data is found, it can make positive identification much faster and easier, as it apparently has with ISIS’s most infamous fiend.