This whole thing is sounding more and more like a spy novel. Did the wife radicalize her husband?

(CNN)Investigators think that as the San Bernardino, California, attack was happening, female shooter Tashfeen Malik posted a pledge of allegiance to ISIS leader Abu Bakr al-Baghdadi on Facebook, three U.S. officials familiar with the investigation told CNN.

Malik's post was made on an account with a different name, one U.S. official said. The officials did not explain how they knew Malik made the post.

A law enforcement official said it appeared that Wednesday's attack -- which left 14 people dead and 21 wounded before the two attackers, Malik and her husband, Syed Rizwan Farook, were killed in a shootout with police -- may have been inspired by ISIS. But none of the officials said that ISIS directed or ordered the attack.

"This is looking more and more like self-radicalization," a law enforcement official said.