A Chechen man linked to one of the Boston Marathon bombing suspects was shot and killed early Wednesday in an unusual encounter with the FBI and other law enforcement officers inside his apartment in Orlando.

According to federal law enforcement officials, the man was being interviewed about whether he and Tamerlan Tsarnaev, one of the bombing suspects, were connected to a two-year-old triple slaying when he attacked an FBI agent and was shot and killed. There were conflicting accounts of what happened in the moments before the man was shot.

One federal law enforcement official said the man, a trained martial-arts fighter with one professional bout, was shot after trying to grab the FBI agent's gun. Two other officials said the man reached for a knife and was shot as he attacked the agent. All three officials spoke on the condition of anonymity because the episode is under official review.