UPDATE | FBI says Calif. shooting being investigated as act of terrorism

AN BERNARDINO, Calif. (AP) — The FBI said toay that it is officially investigating the mass shooting in California as an act of terrorism, while a U.S. law enforcement official revealed that the woman who helped her husband carry out the attack had pledged allegiance to the Islamic State group and its leader on Facebook under an alias.

David Bowdich, assistant director of the FBI's Los Angeles office, would not give further details about why the bureau made the determination, saying at a news conference that "there's a number of pieces of evidence that has pushed us off the cliff."

Syed Farook and his wife, Tashfeen Malik, killed 14 people at the holiday party for his co-workers. The Muslim couple died hours later in a fierce gunbattle with police.

A Facebook official says Tashfeen Malik praised the leader of the Islamic State group in a post at 11 a.m. Wednesday, when the couple were believed to have stormed a San Bernardino social service center and opened fire.

The Facebook official, who spoke on condition of anonymity because the person was not allowed under corporate policy to be quoted by name, said the company discovered the account Thursday. It removed the profile from public view and reported its contents to law enforcement.

Malik, 27, was a Pakistani who grew up in Saudi Arabia and came to the U.S. in 2014 on a fiancée visa. Farook, a 28-year-old restaurant health inspector for the county, was born in Chicago to Pakistani parents and raised in Southern California.