The father of a Chechen man shot dead by the FBI during questioning about his links to the Boston Marathon bombers said on Thursday he wanted the agents tried for "executing" his son.
Ibragim Todashev, 27, was shot by FBI agents in Florida a week ago during questioning at his home about his links to one of the Tsarnaev brothers alleged to have carried out the April 15 Boston bombings.
The FBI said the agents had shot Todashev in self defence after the suspect lunged at them during questioning.
Todashev's father Abdulbaki showed reporters in Moscow what he said were pictures of his son's bullet-riddled body.
The photographs showed at least seven bullet wounds to the body of a young man resembling Ibragim Todashev - including one to the back of the head.
"Today I want justice. I want an investigation, so that these people (the FBI) are sued under US laws," Todashev's father said.
"These are not FBI agents. These are bandits and they must appear in court."
Abdulbaki said he had received the photographs of his son by email from Muslims in Florida.
Local media initially cited investigators as saying he had attacked an FBI agent with a knife. Yet the Washington Post on Thursday quoted a law enforcement official saying Todashev was unarmed.
Investigators said Todashev was on the verge of signing a confession that he and Tamerlan Tsarnaev had played a role in an unsolved triple homicide.
The triple murder took place on September 11, 2011 - the 10-year anniversary of the deadly attacks on the United States - in the Boston suburb of Waltham, according to local media.
All three bodies were found nearly decapitated, covered with marijuana and thousands of dollars in cash.
Todashev's father said he was certain that his son was deliberately killed by the FBI because of the bullet wound to the back of his head.
"This is not a shot that you fire when you come under attack. This is a shot you fire to execute someone," he said.
"Couldn't they just handcuff him? At the very least, they could have wounded him in the foot or shoulder. And here he was - killed execution style."
Todashev's father added that his son must have had information that investigators wanted to keep secret.
"So they silenced him," the father said.