ORLANDO, Fla. (AP) -- A Chechen immigrant was shot to death by authorities in central Florida early Wednesday after he turned violent while being questioned about his ties to one of the Boston Marathon bombing suspects, officials said.

Ibragim Todashev, a 27-year-old mixed martial arts fighter, was fatally shot at his Orlando town house during a meeting with an FBI agent and two Massachusetts state troopers, authorities said. The agent was taken to a hospital with injuries that were not life-threatening.

Three law enforcement officials, speaking on condition of anonymity, said Todashev had lunged at the FBI agent with a knife. However, two of those officials said later in the day it no longer was clear what had happened. The third official had not received any new information.

The FBI gave no details on why it was interested in Todashev except to say he was being questioned as part of the Boston investigation. However, two officials briefed on the investigation said he had implicated himself as having been involved in a 2011 triple-slaying in the Boston suburb of Waltham that authorities believe may have been connected to one of the men behind the bombings.

Several of Todashev's former roommates who were questioned said he knew the older bombing suspect, 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. He's also charged in the slaying of an MIT police officer days later.

Investigators have been trying to establish the scope of the Boston bombings plot. Authorities in Massachusetts said they would investigate whether Tamerlan Tsarnaev had any connection to the unsolved 2011 deaths in Waltham, where three men were found 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.

Two officials who were briefed on the investigation said Todashev made statements implicating himself as being involved in the 2011 Waltham slayings while he was being interviewed by the FBI and Massachusetts state police. Neither of the officials, one of whom had earlier said there was no new information on Todashev lunging at the agent, knew whether Todashev also had implicated Tamerlan Tsarnaev in the killings. The two people, a federal law enforcement official and a Massachusetts state official, were not authorized to release details of the investigation and spoke on condition of anonymity.

Neither official was sure of the extent of Todashev's supposed involvement.

According to friends, Todashev had lived on and off with other Chechens in the Orlando suburb of Kissimmee and had moved to Orlando more recently.

"He's a regular guy; nothing wrong," Saeed Dunkaev said.

Police records, however, suggest he had a hot temper, with arrests in a road rage incident and, more recently, in a fight over a parking space.

Former roommate Khusen Taramov said the FBI was asking questions about a conversation that Todashev had with the elder bombing suspect a month before the Boston 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 bombings in retaliation for the U.S. wars in Iraq and Afghanistan.

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.

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.

Todashev was also arrested by Boston police in 2010 after a road rage incident. Witnesses told police that he argued with two other drivers and cut them off with his vehicle. According to a police report, he yelled, "You say something about my mother, I will kill you."

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Associated Press writers Denise Lavoie in Boston, Pete Yost in Washington and Mike Schneider in Orlando contributed to this report.