The woman who carried out the San Bernardino massacre with her husband had pledged allegiance to the Islamic State group and its leader on Facebook, a U.S. law enforcement official said Friday, providing the strongest evidence to date that the rampage may have been an extremist attack.

The official said Tashfeen Malik made her posts under an alias. A Facebook executive says she 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.

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

The Facebook executive, 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 fiancΘe visa. Farook, a 28-year-old restaurant health inspector for the county, was born in Chicago to Pakistani parents and raised in Southern California.

(Copyright (c) 2015 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

Join our Newsletter for the latest news right to your inbox