Investigators said Williams was at a party at a club in Denver earlier in the evening and an argument took place between members of Williams' group an others at the club, but Williams was not involved in the incident.
Later, after the group left the club in Williams' white stretch Hummer limo, a white SUV pulled up beside it and fired a barrage of bullets into the Hummer, killing Williams.
Two others in the vehicle were wounded, but their injuries were not life-threatening. There were 14 bullet holes in the driver's side of the vehicle and the rear window and driver's window were shot out.
"Losing a fine young man such as Darrent Williams leaves me speechless with sadness," Broncos coach Mike Shanahan said. "We all know that Darrent was an excellent player, but as a person, he was a first-class young man who brightened every room with his smile, attitude and personality. I cannot express how heartsick I feel."
Williams, who is known as "D-Will" to teammates, was a second-round pick out of Oklahoma State. He played in 15 games this season, finishing with 86 tackles and four interceptions.