A Florida prosecutor investigating the FBI’s fatal shooting of a Chechen man said Wednesday that he will release his final report by the end of March. State Attorney Jeffrey L. Ashton is investigating the May 22 shooting of Ibragim Todashev, the 27-year-old friend of suspected Boston Marathon bombers Tamerlan and Dzhokhar Tsarnaev. An FBI agent and two Massachusetts State Police troopers had been questioning Todashev in his Orlando apartment when the FBI agent shot and killed him. The FBI has released little information, saying only that Todashev initiated a violent confrontation. Todashev’s relatives have disputed the bureau’s account. Ashton had previously said his report would be ready early this year.Maria Sacchetti can be reached at email@example.com.