FBI officials have confirmed that the terrorist shot and killed Tuesday by police and federal agents in Boston had been working on a plot to attack police.

Investigators said they moved on Usaamah Abdullah Rahim after intercepting a phone call talking about beheading police officers.  When they approached Rahim, he pulled out a military style knife and threatened the police. He was shot after refusing their demands to drop the weapon and withdraw.

Rahim was described as a 26-year-old security guard who had been “radicalized by ISIS.”  His original plan was to behead Pamela Geller, the woman who had hosted a “Draw Mohammed” contact in Texas that was the target of a failed terror attack.  He changed the plan to target police when he realized it would be too difficult to reach Geller.

“These cases are a reminder of the dangers posed by individuals radicalized through social media,” House Homeland Security Committee Chairma Michael McCaul said at a Wednesday hearing.

Rahim reportedly bought three military style knives from Amazon in late May.

McCaul also said there was evidence of Rahim’s social media communications with ISIS where “going on vacation” was discussed.  He explained that “going on vacation” was code for taking a violent jihad action.

Police have arrested two other men in connection with the plot.