Wilson told jurors that he initially encountered Brown and a friend walking in a street and, when he told them to move to a sidewalk, Brown responded with an expletive. Wilson then noticed that Brown had a handful of cigars, "and that's when it clicked for me," he said, referring to a radio report minutes earlier of a robbery at a nearby convenience store.
Wilson said he asked a dispatcher to send additional police, and then backed his vehicle up in front of Brown and his friend. As he tried to open the door, Wilson said Brown slammed it back shut.
The officer said he pushed Brown with the door and Brown hit him in the face. Wilson told grand jurors he was thinking: "What do I do not to get beaten inside my car."
"I drew my gun," Wilson told the grand jury. "I said, 'Get back or I'm going to shoot you.'"
"He immediately grabs my gun and says, 'You are too much of a ***** to shoot me,'" Wilson told grand jurors. He said Brown grabbed the gun with his right hand, twisted it and "digs it into my hip."
Asked why he felt the need to pull his gun, Wilson told grand jurors he was concerned another punch to his face could "knock me out or worse."
After shots were fired in the vehicle, Brown fled and Wilson gave chase. At some point, Brown turned around to face the officer.
Witness accounts were conflicted about whether Brown walked, stumbled or charged back toward Wilson before he was fatally wounded, McCulloch said. There were also differing accounts of how or whether Brown's hands were raised. His body fell about 153 feet from Wilson's vehicle.
Thousands of people rallied - mostly peacefully - in other U.S. cities on Monday night, and President Barack Obama appealed for calm and understanding, pleading with both protesters and police to show restraint.