Islamic State militants fleeing strongholds in Syria are leaving behind a trove of records detailing everything from the terror group’s finances to personnel documents on individual fighters.

“Their record keeping is phenomenal,” Maj. Gen. James Jarrard told USA TODAY in an interview from Baghdad.

The Islamic State, also called ISIS, kept meticulous records, including directives and orders marked with official stamps.

Over the past three years, the coalition and local forces have seized “hundreds of terabytes” of data from ISIS computers and storage devices in northern Syria, where U.S.-backed forces are operating, according to the coalition headquarters.

Read more: USA Today