In California, the case of an African-American who has been sentenced to death for fourfold murders and who has protested his innocence for decades is to be fully re-examined.

Governor Gavin Newsom said on Friday (local time) that "questions have arisen about the evidence" presented in the trial of Kevin Cooper.

A law firm is said to be investigating the case with the California Release Committee.

In 2004, Cooper's execution was suspended by an appeals court a few hours before the execution. Previously, prominent death penalty opponents in the USA such as civil rights activist Jesse Jackson, human rights organizations such as Amnesty International and the Council of Europe had unsuccessfully appealed to then Governor Arnold Schwarzenegger to pardon Cooper. Schwarzenegger's successors later re-examined the evidence using more modern DNA testing.

Governor Newson said he had taken note of the latest DNA test results and was ordering a "full" review of the trial and appeals process, including old files and evidence, and recent DNA testing, in order to rule on the convict's pardon.

The governor's order does not take a position on Cooper's guilt or innocence.

Was any of his hair placed on the scene?

In 1985, a jury found Cooper guilty of brutally killing Douglas and Peggy Ryan, their ten-year-old daughter Jessica and their eleven-year-old boyfriend Christopher Hughes in June 1983.

The couple's eight-year-old son, Joshua, survived the bloodshed at the Chino Hills home.

Imprisoned for robbery at the time, Cooper had recently fled the prison in Chino Hills, east of Los Angeles.

According to the verdict, he wanted to use the family's car as a getaway vehicle.

Cooper had always protested his innocence.

He had to admit that he had DNA on a hair at the scene, but said the police had placed the hair there to pin the murder on him.

At the time, several witnesses testified that they had seen three white men in blood-smeared clothing who drove away from the house in the family's stolen car on the night of the crime.

The surviving son had also described the perpetrators as white men.

A woman who suspected her boyfriend of having been involved in the crime reported to the police at the time.

She handed over blood-stained trousers and explained that his workshop was missing an ax that resembled one of the murder weapons.

Kamala Harris was also involved in the case

Instead, the investigators arrested Cooper.

The now 63-year-old black man and his lawyers accuse the police of having placed false evidence and destroyed or altered references to other suspects.

On the suspension of Cooper's execution, he had been denied the right to appeal.

Thereupon five judges warned in a written contradiction that the state of California was on the verge of "executing an innocent man."

The current Vice President Kamala Harris also dealt with the Cooper case while serving as attorney general for California.

At the time, critics accused her of blocking new DNA tests.

The last death sentence in California was carried out in 2006.

Newson has announced that there will be no further executions during his term in office.