Ferguson police officer Darren Wilson told investigators he feared for his life during a struggle over his gun with Michael Brown in the moments before the black teenager was killed, information from a civil rights investigation into the incident has revealed.

In the first released accounts of Wilson's interview with investigators, the 28-year-old white officer said he was pinned inside his vehicle during the August struggle and that Brown had reached for his gun, according to information on the investigation obtained by The New York Times.

Forensic evidence collected by the FBI showed that Wilson's gun went off twice inside the car, with one of the bullets hitting the 18-year-old.

Other forensic evidence also showed Brown's blood was on Wilson's uniform, on his gun, as well as inside the door panel of the car, The NY Times reported. Wilson said Brown scratched and punched him several times, causing his face to swell and leaving cuts on his neck.

Wilson's account of the Aug. 9 shooting, however, does not explain why he shot Brown several times after emerging from his vehicle. An autopsy on Brown ordered by his family showed he was shot six times and that two of the bullets struck him in the head.

The officer's account is also different from witnesses who said Brown was surrendering with his hands in the air when Wilson open fired. Brown's death was followed by weeks of protests and rioting in the streets of Ferguson, a predominantly black town with just three black officers on a police force of over 50, according to the Associated Press.

A grand jury is currently underway to determine if Wilson is to face charges for Brown's death. A federal investigation is also underway to determine if Wilson violated Brown's civil rights, but officials told The NY Times the evidence so far does not support filing charges against the officer.

Benjamin L. Crump, a lawyer for Brown's family, dismissed officer Wilson's account.

"The officer's going to say whatever he's going to say to justify killing an unarmed kid. Right now, they have this secret proceeding where nobody knows what's happening and nobody knows what's going on. No matter what happened in the car, Michael Brown ran away from him," Crump told the newspaper.

A grand jury decision is expected by mid-November.