(CNN) -- Ibragim Todashev, shot dead early Wednesday by the FBI in Florida, was "directly involved" in a 2011 triple homicide in Waltham, Massachusetts, a law enforcement official told CNN Wednesday.
Todashev was fatally shot by an FBI agent during questioning about those homicides and whether he played a role in last month's Boston Marathon bombings.
"During questioning, it became clear that he was involved in the murders," said the official on condition of anonymity.
There was a confrontation between him and police during the questioning, according to a second law enforcement official, which led to the shooting and Todashev's death.
The unsolved triple murder received renewed interest after it was learned that Tamerlan Tsarnaev, a deceased suspect in the Boston Marathon attacks, had been a good friend of one of the victims, all of whom were found with their throats slit.
Todashev also had ties with Tsarnaev and had been acquainted with him at a mixed martial arts center near Boston, said a source who was briefed on the bombing investigation.
Todashev had Tsarnaev's phone number in his cell phone, the source said.
Both were members of the mixed martial arts forum Sherdog.com, along with Russian-Canadian boxer-turned-jihadist William Plotnikov, the source said.
Last month, CNN reported that Plotnikov and six others died in a July 2012 firefight with Russian forces in the southwestern republic of Dagestan, while Tsarnaev was visiting the region, according to a source briefed on the investigation.
An FBI agent fatally shot Todashev in Orlando as authorities investigated whether Todashev was connected to the Boston Marathon bombings, a U.S. law enforcement official with direct knowledge of the Boston case told CNN.
Todashev, 27, also knew Dzhokhar Tsarnaev, who is also a suspect in the April 15 bombings, the official said. Dzhokhar Tsarnaev, injured and captured after a manhunt, is being held by authorities. Tamerlan Tsarnaev, his older brother, was killed in a shootout with police shortly after the bombings.
The agent shot in self-defense in the incident, which occurred at Todashev's house, the law enforcement source said.
Todashev was from the Chechnya region, as were the Tsarnaev brothers, the source said.
Todashev was granted political asylum in 2008 but that he came to the US some time before that, a federal law enforcement official told CNN. Todashev has living in the US as a legal resident because of that asylum claim, the official said.
While the man was being questioned by an FBI agent, two Massachusetts State Police troopers and other law enforcement personnel, "a violent confrontation was initiated by the individual," FBI spokesman Jason Pack said.
Todashev was killed and "the agent sustained non-life-threatening injuries," Pack said.
Agents were led to Todashev, who had once lived in Boston, "through investigative leads," the official said.
In the 2011 Massachusetts triple homicide, the Middlesex County district attorney's office said at the time that the victims and two unknown perpetrators appeared to know each other and that it was not a random crime. No suspects were named then. The three victims were killed by "sharp force injuries of the neck," District Attorney Gerry Leone said.
Todashev had been living in the United States as a legal resident since approximately 2008, the source said.
The source added that the FBI had been investigating Todashev for about a month.
The FBI had followed Todashev for days, his friend told CNN affiliate Florida News 13.
Khasuen Taramov told the TV station that Todashev was living in Boston a couple of years ago when he became acquainted with Tamerlan Tsarnaev; after the deadly Boston Marathon bombings, the FBI began questioning and following Todashev and Taramov.
Todashev "wasn't like real close friends (with Tsarnaev), but he just happened to know him," Taramov said. "But he had no idea that they were up to something like that, like bombings and everything, you know what I mean?"
He told CNN affiliate WESH that Todashev and Tsarnaev had spoken by telephone about a month before the bombings.
"It was a complete shock to him," Taramov said.
The two met in Boston, where Todashev had lived and where there is a small, closely knit community of Chechens, said Taramov.
Their telephone conversation before the bombings contained nothing but routine pleasantries, he said. "It was 'How are you doing, how's your family?' That's all."
Taramov said he himself was questioned by the FBI for three hours Tuesday night. Asked what he was asked, Taramov said, "Different kind of questions like 'what do you think about bombings,' 'do you know these guys,' blah blah blah, what is my views on certain stuff."
He said Todashev was not a radical. "He was just a Muslim. That was his mistake, I guess."
Taramov said his friend had told him he had a bad feeling about the direction the investigation was heading. "He felt like there's going to be a setup ... bad setup against him. Because he told me, 'They are making up such crazy stuff, I don't know ... why they doing it. OK, I'm answering the questions, but they are still making up some, like, connections, some crazy stuff. I don't know why they are doing it.' "
Before meeting with the FBI for a 7:30 p.m. interview Tuesday, Taramov said, his friend asked him to take his parents' telephone numbers. "He just told me, 'Take the numbers, in case something happens, if I get locked up, or whatever, call them.' You know what I mean?
"We were expecting to get him locked up, but not getting him killed. I can't believe it."
Todashev was unemployed and had been living on insurance money after surgery for an accident. "He used to be a fighter, MMA fighter," Taramov said, in a reference to mixed martial arts.
Todashev was arrested this month on a charge of aggravated battery after getting into a fight over a parking spot with a man and his son outside an Orlando mall.
The son was taken to a hospital with head injuries, a split upper lip and several teeth knocked out of place, the Orange County Sheriff's Office said in a report.
"Todashev said he was only fighting to protect his knee because he had surgery in March," the report said. He told the police that he was a former mixed martial arts fighter, it said.
Todashev, described as 5-foot-9 and 160 pounds, was released on $3,500 bond.
Asked about the incident, Taramov downplayed it. "He had a fight in the parking lot, the two guys jumped on him ... pretty much he just defended himself against two," he told WESH. "The only mistake: he did kick their ass and left."
Todashev had recently gotten his green card and had been planning to visit his parents in Chechnya, and then return to the United States, but canceled the plans, Taramov said.
Now, he added, he was planning to call his friend's parents.
An FBI shooting-incident review team was expected to arrive within 24 hours in Orlando, said Special Agent Dave Couvertier, an FBI spokesman. Such reviews are standard when an agent is involved in a shooting.