The female shooter in the Wednesday terror attack in San Bernardino, Calif., posted an oath of allegiance on Facebook to ISIS and its leader Abu Bakr al-Baghdadi during the attack, CNN has reported.

Tashfeen Malik made the post under a pseudonym. The New York Times reported that the investigation showed that Malik and her husband, Syed Rizwan Farook, had been erasing the trail of their online activity in the days leading up to the attack. This activity has suggested to authorities that the attack was premeditated.

Thomas Joscelyn, a senior fellow at the Foundation for Defense of Democracies, gave a possible explanation for Malik’s oath of loyalty to Baghdadi during the attack. Joscelyn noted on Twitter that according to Dabiq, ISIS’ online magazine, “believers shouldn’t die in a state of disobedience & should swear allegiance before death.”

Law enforcement sources told CNN on Thursday that Farook had been in contact with at least one individual who was involved in terror and was being investigated by the FBI.

It has also emerged that Farook had jihadist views regarding Israel. The Times reported that in a recent conversation with one of his eventual victims, Nicholas Thalasinos, Farook was heard denying that Israel is the Jewish homeland and saying that Jews didn’t belong in Israel.

The couple opened fire on the Inland Regional Center in San Bernardino, where Farook was employed, on Wednesday, killing 14 and wounding at least 17 others. According to subsequent reports, they left an explosive device at the center and had a bomb-making laboratory in their home.

[Photo: CNN / YouTube ]