Officer Darren Wilson told investigators that he was pinned down in his police car and feared for his life during a struggle for his gun with Michael Brown, just before he shot the unarmed teen to death on Aug. 9 in Ferguson, Missouri. Wilson told authorities that Brown reached for his gun, which FBI forensics investigators said was fired twice in the squad car, according to federal officials briefed on the civil-rights probe. Forensics tests found Brown’s blood on the gun, an interior door panel, and on Wilson’s uniform. The officials said that while the federal investigation was continuing, the evidence so far did not support civil-rights charges against Wilson. The officer’s testimony contradicts some witness accounts.