SAN BERNARDINO - A U.S. law enforcement official says the wife of the couple blamed in the deadly California shootings pledged allegiance to the Islamic State group and the terror group's leader on Facebook using an alias then deleted the messages before the attacks.

Specific details about Tashfeen Malik's postings weren't disclosed Friday by the law enforcement official, who spoke on condition of anonymity because this person was not allowed to discuss an ongoing investigation.

The remarkable disclosure about Malik's online activities provided the first significant details suggesting a motive for her participation with her husband, Syed Farook, in the shootings that killed 14 people and injured 21.

Malik was a Pakistani woman who came to the U.S. in 2014 on a fiancee visa before Farook married her in California.