WASHINGTON — Two ISIS fighters notorious for imprisoning and murdering Western hostages were captured on the battlefield in Syria in January, according to three U.S. officials.

The men were part of a group of four jihadis dubbed the Beatles by observers because of their British accents, and were caught by the Syrian Democratic Forces (SDF), a Kurdish and Arab militia fighting both ISIS and the Assad regime. Their capture was first reported by The New York Times.

Officials identified the two as Alexandar Amon Kotey and El Shafee Elsheikh, and they were the last of the four Beatles on the battlefield. The best-known member of the group, Mohammed Emwazi, aka Jihadi John, who was seen and heard on videos beheading prisoners, was killed in an airstrike in Raqqa, Syria, in November 2015. The fourth member, Aine Davis, is in Turkish custody. All four men were from West London.

The four men tortured their hostages, according to U.S. officials, and are linked to more than two dozen beheadings. Emwazi was suspected of killing Americans James Foley and Steven Sotloff.

According to the Times, U.S. officials were told in mid-January that the militia might be holding Kotey and Elsheikh, and U.S. forces used biometric data to confirm their identities.

The SDF and the Coalition have been exploiting information gleaned from the two men and using it for active missions, according to two officials.