A convicted murderer faces execution in Texas after jurors consulted the Bible while deliberating on his sentence.

Amnesty International has appealed to the state to commute the sentence on Khristian Oliver, 32, who is due to die on November 5.

He was sentenced to death in 1999 for murdering a man whose home Oliver was burgling. The victim was shot in the face and beaten with his own rifle.

It later emerged that while deciding whether he should be given the death penalty, jurors consulted the Bible. Four jury members admitted that several copies had been in the jury room and that highlighted passages were passed around.

At one point, a juror reportedly read aloud from a copy, including the passage: "And if he smite him with an instrument of iron, so that he die, he is a murderer: the murderer shall surely be put to death."

Defence lawyers argued in appeals that jurors had been improperly influenced by the Bibles but the trial judge rejected the claim, a decision upheld by a Texas appeals court.

The US constitution calls for the separation of state and religion. In 2005, the state supreme court in Colorado overturned a death penalty on a convicted murderer because jurors had consulted the Bible while deliberating over his sentence.

Commuting Robert Harlan's sentence to life imprisonment without parole, the court ruled that the Bible constituted an "improper outside influence" and a reliance on what it called a "higher authority".

However, a federal appeals court ruled last year that while the Bible should not have been allowed into the deliberation room at Oliver's trial, there was no clear evidence to indicate they had influenced the jurors' decision. In April this year, the US Supreme Court refused to hear Oliver's appeal.

Kate Allen, Amnesty International's UK director, said Oliver's trial was a "travesty".

"Religious texts provide consolation and spiritual guidance for billions of people the world over, but this use of the Bible to decide life or death in a capital trial is deeply, deeply troubling," she said.

Telegraph.co.uk