Ibragim Todashev, the Chechen acquaintance of one of the accused Boston bombers, was shot roughly a half-dozen times in several seconds by an FBI agent after he twice lunged at the officer with a metal stick, according to senior federal law enforcement officials.

The description of events follows a series of unofficial and contradictory accounts that surfaced after the shooting in Todashev’s Orlando apartment May 22, including early reports — later said to be inaccurate — that he attacked the agent with a knife.

Under FBI regulations regarding the use of deadly force, agents can discharge their weapons if they feel they are threatened with death or serious bodily injury. The FBI’s shooting incident review team is investigating what happened in Orlando, and its findings will be examined by a Shooting Incident Review Group, which consists of members of the FBI and the Justice Department.

A U.S. law enforcement official, speaking on the condition of anonymity, said Todashev was shot “in the range of six times.” His family, which released photos of the body through the Florida chapter of the Council on American-Islamic Relations, said Todashev was shot in the chest, head, shoulder and arm.

His family has questioned whether the shooting was justified and is demanding the release of the autopsy report and other medical records from the Orange County Medical Examiner’s Office. The records remain sealed while the investigation is open, and officials at the Medical Examiner’s Office referred calls to the FBI.

“The family and our office has already submitted requests for [the records’] release,” said Thania Diaz Clevenger, civil rights director of CAIR Florida. “However, it is unknown at this time when the Medical Examiner’s Office will have the FBI’s authorization to release the records. The family and our office is also interested in obtaining any official police reports produced from federal or local departments. If the records are unjustly withheld, we will take any justified legal action we deem necessary.”

Todashev, who was not a suspect in the Boston Marathon bombing, was allegedly providing a written confession about a 2011 triple homicide in Waltham, Mass., when the confrontation occurred, the officials said. Law enforcement officials said he had also implicated accused Boston bomber Tamerlan Tsarnaev in the murders. Tsarnaev was killed in a shootout several days after the attack at the marathon.

There was also a Massachusetts state police officer in the room at the moment of the Orlando shooting, but he did not fire his weapon. Another state trooper and an Orlando police department officer were just outside the apartment, the officials said.

Todashev had not been arrested, but the officers had begun to discuss bringing him in because of the confession he had started to write.

Just before the shooting, the Massachusetts officer had warned the FBI agent in a text message that Todashev, a mixed martial arts expert, appeared to be getting agitated and the agent should be careful, according to the officials. Almost immediately, Todashev turned over a table and attacked the agent with what was probably part of a broom handle, officials said.

Some details of the incident were first reported in Friday’s New York Times and on CBS News.

FBI shootings are rare. In a 17-year period, ending in 2012, there were nearly 200 shootings, according to news reports, but it was unclear how many of those shootings resulted in deaths. Over the past year, there have been at least five fatal shootings involving the FBI, including one that took place during the rescue of a young child being held hostage in Alabama, according to reports.

The FBI was not able to immediately provide the exact number of fatal shootings by its agents over the past several years.

Julie Tate contributed to this report.