An Alabama man was sentenced to death Wednesday for the 2008 slaying of an Auburn University student from Marietta.

A Lee County, Ala., Circuit Court jury last November convicted Courtney Lockhart of murdering 18-year-old Lauren Burk and recommended that he be sentenced to life in prison without parole.

But on Wednesday, Judge Jacob A. Walker III overruled the jury's recommendation and sentenced the Smith’s Station, Ala., man to death by lethal injection.

Lockhart's mother screamed out and cried when the judge sentenced her son to death by lethal injection. She had to be comforted by relatives.

Lockhart will receive an automatic appeal under state law.

Lockhart’s sentencing was originally scheduled for late January, but was delayed at the request of prosecutors.

Burk, a 2007 graduate of Walton High School, was a freshman at Auburn when she was abducted from a campus parking lot on March 4, 2008. She was later found dying after being shot in the back along a rural road about four miles north of the Auburn campus.

Lockhart, 26, was arrested three days later in Phenix City, Ala.

The Iraq war veteran, who admitted on tape to abducting, robbing and holding a gun that fired and killed Burk, had pleaded not guilty by reason of mental disease or defect.

Speaking to a nearly full courtroom, Judge Walker said Lockhart was suspected in a string of five robberies that occurred in southeast Alabama and west Georgia around the same time as the slaying, but jurors did not hear about those crimes during the murder trial.

"It is the court's opinion that this would have undermined the jury's decision" for life without parole, he said, sentencing Lockhart to die. The judge continued talking, but his words were drowned out by screams from Lockhart's mother.

Defense lawyer Jeremy Armstrong said he was disappointed in the death penalty, which he suggested would only prolong the case for the Burk family since appeals can last as long as 25 years.

"The override will get more scrutiny on appeal," he said.

Outside court, Lauren's mother, Viviane Guerchon, said her daughter loved trees and babies and was planning a career in photography and marketing.

"The pain will be going on for ever," she said.

The Associated Press contributed to this article.