An Irvine man was sentenced Friday to 21 years to life in prison after being convicted of murder for drunkenly crashing his truck into a car and killing a teenage girl, the Orange County district attorney announced.

Austin Jeffrey Farley, 28, had more than twice the legal limit of alcohol in his blood on May 29, 2011, when he ran a red light turning left at the intersection of Culver Drive and Irvine Boulevard, crashing into a Mercedes-Benz sedan carrying a father, his daughter and three of her friends.

Ashton Sweet, 14, was sitting in the left rear seat of the sedan and died about four hours after the crash from brain swelling, a skull fracture and other trauma caused by the impact.

Farley had been drinking earlier that night, according to the D.A.

He and his girlfriend took a cab to a bar after leaving his truck at a friend's home in Irvine. After drinking, they took a cab back to the house and Farley drove his truck to take his girlfriend to get food at about 1 a.m. when he hit the Mercedes, according to the D.A.

Farley had previously been convicted of a misdemeanor charge of driving under the influence in 2009.

A judge informed Farley then that he could be charged with murder if he killed someone while driving drunk.

On Oct. 7, a Los Angeles County jury convicted Farley of one felony count each of second-degree murder and driving under the influence of alcohol causing injury.

At the sentencing Friday, Sweet's mother Elizabeth read a statement about the impact of Farley's crime.

"When you talk about nightmares, they have already passed. This nightmare does not pass. My soul feels weary, as if I've lived far too long," she said, according to a news release from the D.A.

— Jeremiah Dobruck

Twitter: @jeremiahdobruck