The governor of Texas has halted the execution of a getaway driver in a botched 1996 robbery that ended with an accomplice shooting a man dead.
Foster was 19 when he and three others went on a crime spree
Governor Rick Perry commuted Kenneth Foster's death sentence to life after a recommendation from the parole board.
Foster, now 30, was convicted under a Texas law allowing accomplices to a crime that results in murder to face capital punishment.
Mr Perry called the decision to commute the sentence "right and just".
Human rights groups had urged clemency for Foster.
Prosecutors successfully argued during his trial that Foster displayed "reckless disregard for human life".
The Texas "law of parties" abolishes the distinction between the main perpetrator of a crime and an accomplice, allowing both to be held equally culpable.
Point blank range
In August 1996, Foster was driving a car with Mauriceo Brown and two other young men as they carried out a series of robberies in San Antonio while all four were high on marijuana.
In the course of the night, Brown jumped out of the car and got into an argument with 25-year-old Michael LaHood, demanding his wallet and car keys.
When Mr LaHood could not produce them, Brown shot him in the face at point blank range, before returning to the car which was parked some 30m away.
Prosecutors argued that Foster "should have anticipated" that his friend had a gun and that he was likely to use it to kill.
Amnesty says there was no evidence demonstrating that Foster could know a murder would be committed.
"In essence, Kenneth Foster has been sentenced to death for leaving his crystal ball at home," Larry Cox, executive director of Amnesty International USA, said of the case.
"Allowing his life to be taken is a shocking perversion of the law."
The gunman, Brown, was executed in 2006.
Foster was due to face the same fate at 2300 (0400 GMT Friday).
The two other men are serving life sentences.
Last week Texas carried out its 400th execution since reintroducing the death penalty in 1976.
Johnny Ray Conner, 32, was put to death by lethal injection for the 1998 fatal shooting of a grocery store clerk.
Earlier in the week, the EU urged Texas to end the "cruel and inhumane" practice, but Texas's governor said it was a "just and appropriate" punishment.