This May 4, 2013 police photo provided by the Orange County Corrections Department in Orlando, Fla., shows Ibragim Todashev after his arrest for aggravated battery in Orlando. Todashev, who was being questioned in Orlando by authorities in the Boston bombing probe, was fatally shot Wednesday, May 22, 2013 when he initiated a violent confrontation, FBI officials said. AP Photo/Orange County Corrections Department FBI investigators walk near the crime scene of an apartment where a man was shot by an FBI agent, Wednesday, May 22, 2013, in Orlando, Fla. The man who was shot and killed by the agent early this morning was friends with the Boston bombings suspects, according to a friend of the victim. In this May 4, 2013 police mug provided by the Orange County Corrections Department in Orlando, Fla., shows Ibragim Todashev after his arrest for aggravated battery in Orlando. Police officers block the entrance to an apartment complex where man was fatally shot, Wednesday, May 22, 2013, in Orlando, Fla. The FBI says the man, being questioned by authorities in the Boston bombing probe, was fatally shot when he initiated a violent confrontation. An FBI investigator enters the apartment where a man was shot by an FBI agent, Wednesday, May 22, 2013, in Orlando, Fla. (AP) - A Chechen immigrant who was being questioned about his ties to one of the Boston Marathon bombing suspects was shot to death early Wednesday after he lunged at an FBI agent with a knife, officials said. Ibragim Todashev, a 27-year-old mixed martial arts fighter, was gunned down by authorities at his Orlando home during a meeting with the agent and two Massachusetts state troopers, authorities said. The agent was taken to a hospital with injuries that were not life-threatening. The FBI gave no details on why it was interested in Todashev except to say that he was being questioned as part of the Boston investigation. But some of his former roommates who were questioned as well said that Todashev knew one of the bombing suspects, Tamerlan Tsarnaev, from mixed martial arts fighting in Boston and that the FBI was asking about him. Public records show Todashev lived in Watertown, Mass., just outside Boston, last year. Tamerlan Tsarnaev, an aspiring boxer, was killed in a shootout with police days after the April 15 bombings. His younger brother, Dzhokhar, survived and is charged with carrying out the attack that killed three people and wounded more than 260. Investigators have been trying to establish the scope of the plot. In addition, authorities in Massachusetts said they would investigate whether Tamerlan Tsarnaev had any connection to an unsolved 2011 slaying in the Boston suburb of Waltham, where three men were found dead in an apartment, their throats slit and marijuana sprinkled over their bodies. One of the victims was a boxer and a friend of Tsarnaev's. Todashev had lived on and off with other Chechens in the Orlando suburb of Kissimmee and had moved to Orlando more recently, friends said. "He's a regular guy, nothing wrong," Saeed Dunkaev said. Muslin Chapkhanov, another former roommate, said Todashev knew the older Tsarnaev brother. Todashev "was living in Boston and I think he trained with him," Chapkhanov said. Former roommate Khusen Taramov said the FBI was asking questions about a conversation Todashev had with the elder bombing suspect a month before the Boston Marathon attack. The Tsarnaev brothers have roots in the turbulent Russian regions of Dagestan and Chechnya, which have become recruiting grounds for Islamic extremists. Investigators have said the brothers carried out the Boston bombing in retaliation for the U.S. wars in Muslim Iraq and Afghanistan. Two law enforcement officials, speaking on condition of anonymity because they were not authorized to release details of the investigation, said Todashev came at the FBI agent with a knife before he was shot. An FBI team was dispatched from Washington to review the shooting, standard procedure in such cases. Todashev was arrested earlier this month on a charge of aggravated battery after getting into a fight over a parking spot with two men - a father and son - at an Orlando shopping mall. The son was hospitalized with a split lip and several teeth knocked out, according to a sheriff's report. Todashev claimed self-defense. "Also by his own admission Todashev was recently a former mixed martial arts fighter," the arresting deputy said in his report. This skill puts his fighting ability way above that of a normal person. Todashev was released on $3,500 bail after his May 4 arrest. His attorney, Alain Rivas, didn't immediately respond to a call for comment Wednesday. Police tape blocked off the complex of townhouses near Universal Studios where Todashev was shot. Associated Press writers Denise Lavoie in Boston, Pete Yost in Washington and Mike Schneider in Orlando contributed to this report.