NEW: Two of four British ISIS members who presided over executions of western hostages were captured by Syrian Democratic Forces and are being interrogated by U.S. forces, senior official confirms to @ABC.

NEW: Two of four British ISIS members who presided over executions of western hostages were captured by Syrian Democratic Forces and are being interrogated by U.S. forces, senior official confirms to @ABC.

— ABC News (@ABC) February 8, 2018