The prosecution had originally asked for the death penalty for Aaron McKinney, 22, but reached an agreement approved by the victim's family.

McKinney, a high school dropout, is the second man to be convicted in the case.

Earlier this year, his co-defendant Russell Henderson pleaded guilty to murder and kidnapping and was also sentenced to two life terms.

The 21 year-old was left to die

The jury of seven men and five women found McKinney not guilty of first degree murder, but convicted him of felony murder - a killing carried out during the course of another crime.

McKinney was also found guilty of aggravated robbery and second degree murder.

Under the terms of the agreement he has given up the right of appeal.

McKinney, who did not take the stand during the trial, told the court he would feel eternal remorse for what he had done.

National outrage

The brutal nature of the crime stunned the nation, prompting vigils, demonstrations and calls for anti-hate crime legislation.

Police testified that McKinney and his friend Russell Henderson lured Shepard from a bar in Laramie, pistol-whipped him, tied to a fence outside of town and left him to die.

Shepard, 21, was not found for some 18 hours. He died five days later in hospital at Fort Collins, Colorado, without regaining consciousness.

Prosecutors said McKinney was like a "wolf" preying on his smaller victim.

Defence lawyers argued that he never intended to kill Shepard.

"Gay panic"

They attempted to use a "gay panic" defence, based on the theory that some men are prone to an uncontrollable, violent reaction when propositioned by a homosexual.

They told the court that McKinney was crazed by drugs and alcohol and flew into a blind rage when Shepard allegedly made an unwelcome sexual advance which revived memories of childhood sexual abuse.

But the judge, Barton Voigt, disallowed this line of defence, ruling that it was prohibited under Wyoming law.

As a result , the defence rested its case earlier than expected after calling only seven witnesses.

McKinney's former girlfriend, Kristen Price, will go to trial next year on charges on providing a fake alibi and helping destroy evidence.