A man and a woman suspected of taking part in a shooting that killed 14 people and wounded 17 at a Southern California social services agency on Wednesday died in a shootout with police hours later, authorities said.

A Muslim advocacy group said one of the suspects was Syed Farook, and introduced a man as Farook's brother-in-law, who said he had no idea what might have motivated the attack. He said his relative was a U.S. citizen.

Officials have yet to publicly identify any suspects.