The National Security Administration’s massive collection of data about Internet traffic and telephone calls could prove crucial in tracking suspected terrorist networks, according to a report.

The Wall Street Journal reported Tuesday that a cache of NSA data is being used to help the FBI try to find an ISIS leader.

According to the report, the collection could help identify the person behind the attacks in the U.S. and overseas.

It is not clear how much the NSA has collected about U.K. or U.N. intelligence sources.