Adam Acorn, 23, of Tucson faces between three and 23 1/4 years in prison after pleading guilty to manslaughter in the September 2011 death of his brother.

Acorn was driving east on East Sixth Street when he missed a curve just west of North Country Club Road and hit a tree. Nicholas Acorn, 23, a front-seat passenger, died later of his injuries.

Another front-seat passenger, a woman in her 20s, was taken to a hospital with serious injuries, and two men in the back seat, also in their 20s, had minor injuries.

Acorn pleaded guilty Wednesday in Pima County Superior Court to manslaughter, aggravated assault, endangerment and driving under the influence, said defense attorney Brick Storts.

He will be sentenced April 29 by Judge Howard Fell.