"I want justice. I want an investigation," Abdulbaki Todashev told reporters in Moscow after applying for a U.S. visa so he could pick up his son's body in Orlando, Fla., where he died.
"They come to your house like bandits, and they shoot you," he said.
Ibragim Todashev, 27, was an acquaintance of Tamerlan Tsarnaev, the alleged planner of the deadly April 15 Boston Marathon bombings, but didn't know him well, Abdulbaki Todashev said.
Tsarnaev, 26, was killed in a shootout with police four days after the two bombs exploded near the race's finish line. His younger brother, Dzhokhar Tsarnaev, 19, was captured later that day and remains in custody.
Abdulbaki Todashev displayed photographs for reporters of his son's body -- the same photos shown by an Islamic civil rights advocacy group in a Florida news conference Wednesday evening. The photos showed six shots to the body and a "control" shot to the back of the head, the elder Todashev said.
Abdulbaki Todashev said his son had planned to return to Chechnya a week ago, but appeared to have canceled his tickets before he was killed May 22.
The father said the FBI may not have wanted his son to return to Russia.
"Maybe my son knew some sort of information that the police didn't want to get out," he said in remarks quoted by The Washington Post.
"They shut him up. That's my opinion," he said.
Hours after the Moscow news conference a senior law enforcement officer told The New York Times in a story from Washington that Ibragim Todashev was shot by the FBI agent after he knocked the agent to the ground with a table and ran at him with a metal pole or broom stick.
The agent fired several shots, striking Todashev and knocking him backward but not killing him, the officer told the Times. Todashev again charged at the agent, who then fired several more shots, killing Todashev, the officer said.
A detective in the room did not fire his weapon, the official said.
The Thursday Times account differed from a Wednesday Washington Post account, which cited two law enforcement officers as saying Todashev overturned a table and lunged at the agent but had no weapon.
One official cited by the Post said all other law enforcement officials had stepped out of the room shortly before the confrontation, leaving the FBI agent alone with Todashev.
On the day of the shooting, federal law enforcement officials provided differing accounts of the episode, first saying Todashev had a knife, then saying he "exploded" at the agent and might have had a pipe or might not have had anything in his hands.
Some law enforcement officials also first suggested Todashev tried to grab the FBI agent's gun.
Under FBI guidelines, agents can shoot at someone if they believe the person is a threat to themselves or someone else.
The FBI had no immediate comment on the latest account. It declined to comment on the Post's account.
The episode is being reviewed by FBI investigators and the district attorney in Orlando, officials said.
"The review process is thorough and objective and conducted as expeditiously as possible under the circumstances," the FBI said in a statement after the Post cited the officials as saying Todashev was unarmed. The Wednesday statement said the review could take several months.
The shooting occurred after a Boston FBI agent and two Massachusetts State Police detectives interviewed Todashev in his apartment about the possible role he and Tsarnaev had in a Sept. 11, 2011, triple murder in Waltham, Mass., near Boston, the FBI said May 22.
Todashev confessed to involvement, implicated Tsarnaev and was starting to write a confession statement when he picked up his side of the table and threw it toward the agent, several officials said.