Abdulbaki Todashev spoke at a news conference in Tampa, Fla., in front of a backdrop of photographs showing his son, Ibrahim, as a child and man, the Orlando Sentinel reported. Todashev said Ibrahim, 27 when he died in May, "was a very good boy and he wanted to live."
Todashev said his son had had knee surgery shortly before the FBI interview and was disabled from that.
The father, who recently arrived from Russia, read a statement through an interpreter and would not answer questions.
"We aren't going to comment on what we think happened inside that room," Eric Ludin, a lawyer for the family, said.
The Todashev family and the Council on American-Islam Relations are conducting their own investigation of the shooting, using private detectives. The FBI has released little information about what happened.
Ibrahim Todashev, a mixed martial arts enthusiast and acquaintance of Tamerlan Tsarnaev, was shot while he was being questioned by the FBI and Massachusetts State Police. An FBI agent was wounded.
The FBI has blocked the autopsy report from being released.
Tamerlan Tsarnaev was killed in a shootout with police a few days after the April 15 bombing. His younger brother, Dzhokhar, is in custody.
Hassan Shibly, who heads Florida CAIR, told the Sentinel the group is trying to help the Todashev family find out what happened and decide on what steps to take.
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