The FBI has cleared the agent of wrongdoing who shot and killed a friend of Marathon bombing suspect Tamerlan Tsarnaev while he was being interviewed at his house in Florida.

Events surrounding the shooting have been shrouded in mystery as the FBI and Justice Department have refused to release much information about what happened that caused the agent to open fire on a man who was not armed with a gun. A report by a Florida prosecutor is also expected to exonerate the agent, but the prosecutor's office denied that a final determination had been made.

New York Times:

Civil rights and civil liberties groups criticized the F.B.I.’s findings, saying that it was not surprising that the F.B.I. had once again determined that one of its agents had not violated its policy on the use of force.

“We still don’t know what happened,” said Carol Rose, the executive director of the A.C.L.U. of Massachusetts, “nor why explanations from those who were present at the shooting death have been inconsistent, suggesting at various times that Mr. Todashev allegedly threatened agents, including with a knife, a pipe, a stick or pole, an agent’s gun, the deceased’s martial arts training, or even a samurai sword.”

The New York Times reported in June that F.B.I. agents fatally shot about 70 “subjects” and wounded about 80 others from 1993 to early 2011 — and in every case, the agent’s use of force was determined to be justified. The information was based on documents obtained through a Freedom of Information Act lawsuit.

All findings released to the public since 2011 have also cleared agents involved in intentional shootings.

The inquiry into the Todashev shooting stood out from other such episodes involving the F.B.I., which are typically not investigated outside the Justice Department.

The F.B.I. agent who shot Mr. Todashev was based in the Boston field office, and he and two Massachusetts state troopers had traveled to Florida for the interrogation after investigators uncovered evidence tying him to the bombing suspects, Tamerlan and Dzhokhar Tsarnaev. During the interview, Mr. Todashev, who had lived in the Boston area before moving to Florida, said he and Tamerlan Tsarnaev were behind a 2011 triple homicide in Waltham, Mass. But Mr. Todashev said he knew nothing about the bombing plot.

The initial accounts conflicted about what occurred between the F.B.I. agent, whose name has not been released, and Mr. Todashev.

The first reports from law enforcement officials said that Mr. Todashev had attacked the agent with a knife. Later, the officials said, Mr. Todashev was unarmed. Another later report said Mr. Todashev had knocked the agent to the ground.

While the agent tried to stand, according to that version of events, the agent drew his gun. Mr. Todashev then charged at him with a pole, and the agent fired several shots, knocking him backward.

Why the confusion? Because the FBI rarely shares information with local law enforcement about shootings involving their agents. I doubt the Florida prosecutor got much cooperation from the FBI or Justice during his investigation either.

It's pretty incredible that no FBI agent has been held accountable for any shooting in the last 20 years. The FBI sharpshooter who killed Randy Weaver's wife Vicki was indicted for manslaughter by a local grand jury but a federal court threw it out based on the concept of "sovereign immunity."

That said, the agent apparently suffered an injury to the back of his head and it's clear that Mr. Todashev attacked the agent - armed or not. .

In addition to the FBI report and the report of the prosecutor, the Justice Department has compiled its own report on the incident and it's likely that all the reports will be released soon.