Human rights, religious and anti-death penalty groups are calling on the US state of Texas to stop the execution of a man who may be brain-damaged.
The campaign follows that against the judicial execution of a Briton in China suffering from mental health problems.
Kenneth Mosley, aged 51, faces execution by lethal injection on Thursday 7 January 2010, unless Texas governor Rick Perry intervenes.
Amnesty International supporters are sending 'urgent action' appeals to Governor Perry and to the Texas Board of Pardons and Paroles.
Mosley was sentenced to death in 1997 after being found guilty of the murder of a police officer, David Moore, in an attempted bank robbery in the city of Garland, Texas.
At his trial, Mosley testified that he had not intended to shoot Moore and there were conflicting eyewitness accounts as to whether the shooting appeared intentional.
Meanwhile, the trial jury was told nothing about Mosley's upbringing, which was marked by violent abuse from his father and his exposure to toxic pesticides that may have seriously damaged his brain. Neither did the jury hear of his severe depression and a long history of cocaine and alcohol abuse as 'self-medication'.
After his trial, two psychologists concluded that Mosley suffered from frontal lobe dysfunction. Another psychologist said he had "generalised brain impairment as well as damage to specific areas in both the right and left sides of his brain." The third expert said that the "primary cause" of his "neuro-cognitive deficits" was "his lengthy and varied exposures to toxic chemicals at a vulnerable developmental stage."
Amnesty International's UK Director, Kate Allen commented: "Executions are always cruel and unnecessary, but for Texas to put to death a man who might be brain-damaged would be utterly unforgivable."
She added: "Our thoughts are with the family of Officer Moore at this time but even those that support the death penalty ought to admit it's totally wrong to execute a man like Kenneth Mosley."
"As with many other US capital cases, a jury has made a decision over Mosley's fate without hearing the full story. Governor Rick Perry should, in all conscience, stop this execution," she said.
Texas is one of 35 US states to retain the death penalty. The USA has seen a fall in the number of executions in recent years, but it still executes dozens of people every year - in 2009 there were 52 executions.
Kenneth Mosely is one of 342 inmates (332 men, 10 women) on death row in Texas.
From 1973 to the present, 139 people have been released from death row in the USA on the grounds of innocence (an average of approximately three exonerations per year).
Since 1976 the USA has executed 1,188 people. Some 3,300 prisoners remain on death row.