An FBI agent in Orlando shot dead a man whom the agency says turned violent as he was being questioned in connection with the Boston Marathon bombing investigation late Tuesday.

The suspect was identified by the FBI as Ibragim Todashev, 27, of Orlando.

FBI spokesman Paul Bresson said the agent involved in the shooting on Peregrine Avenue near Kirkman and Vineland roads, near Universal Orlando, acted on an imminent threat and shot Todashev during an interview. The FBI agent was "conducting official duties" when Todashev was shot, agent Dave Couvertier said in a statement.

A source told FOX 25 News in Boston that Todashev was being questioned by an FBI agent from Boston about an unsolved triple murder in Waltham, Mass. The source said Todashev became violent during the interview and was shot by the agent.

Khusen Taramov, a man at the scene who identified himself as a friend of Todashev's, said Wednesday that Todashev knew Tamerlan Tsarnaev, the older brother suspected in the April 15 bombings that killed three and injured more than 260.

Taramov said he and Todashev had no connection with the Boston bombings, but the FBI had been questioning them since then. Taramov said Todashev had lived in Boston at one point, and he and Tsarnaev were mixed-martial-arts fighters. He said the two were not friends, just acquaintances through their MMA fighting.

"He used to talk on the phone with him [Tsarnaev]," Taramov said of Todashev. "They talked last time a month ago. After the bombing, I couldn't believe it," he said.

Taramov said ever since the bombings, he and Todashev had been questioned and followed by the FBI.

"The FBI kept asking, 'What's the connection?' But there is no connection... no connection."

Taramov said Todashev had planned to return to Chechnya but canceled his tickets.

"Me and him and my friends, we knew this was going to happen. That's why he wanted to leave the country," Taramov said. "But he canceled the tickets. The FBI's been pushing him, 'Don't leave, don't leave.' So he decided to stay," he said....