Rahim's brother, an Imam in a mosque in Oakland, tweeted that, before Rahim was shot, he was on the phone with his father and his last words were, "I can't breathe."
"It's unfortunate that it feels like we've become a place where we shoot first and ask questions later," said Ali Samee, a member of the mosque. "This is deeply troubling and we're all very, very hurt right now."
Boston community members who viewed the tape Wednesday said it did not appear Rahim was on the phone at the time of the shooting.
Usaama Rahim had been under surveillance by a Joint Terrorism Task Force and spreading online propaganda for the Islamic State of Iraq and Syria (ISIS) before he was shot and killed on Tuesday, said U.S. Rep. Michael McCaul, who chairs the House Homeland Security Committee.
The task force was investigating Usaama Rahim because he had been "communicating with and spreading ISIS propaganda online," the Texas Republican said. "These cases are a reminder of the dangers posed by individuals radicalized through social media."