Marcellus Williams: Missouri set to execute death row inmate despite new evidence suggesting he is innocent

A death row inmate in the US state of Missouri is about to be executed – despite new DNA evidence suggesting he is innocent.

Marcellus Williams, now 48, was found guilty of the August 1998 murder of Lisha Gayle, 42, at home in St Louis. He was convicted and sentenced to death three years later.

He is scheduled to be killed by lethal injection at 6pm on Tuesday (12am GMT).

However, new evidence suggests Williams may be innocent, as DNA found on the knife used to kill Ms Gayle does not match his.

Prosecutors claim Williams was burgling his victim’s home when she discovered him and he stabbed her repeatedly. He has always maintained his innocence.

Williams’ lawyers have now asked the US Supreme Court to intervene in a desperate final bid to stop his execution. They are also appealing to Missouri’s Republican governor, Eric Greitens, to grant him clemency.

His legal team says technology not available during the initial investigation shows DNA found on the murder weapon matches that of an unknown male and not Williams.

His lawyer, Kent Gipson, told Al Jazeera: "We petitioned the court to look at the new evidence on August 14th, and less than 24 hours later they decided based on the court files that the execution should go ahead anyway. This is unprecedented.

"There is no physical evidence, no eyewitnesses that directly connect Williams to the murder, the DNA on the weapon wasn't his, the bloody footprint at the murder scene wasn't from Williams' shoe and was a different size, and the hair fibres found weren't his.

“It was someone else that killed Gayle, not Williams."

Supporters have also argued that Williams’ lawyer during his initial trial was inundated with work and did not have enough time to prepare their case – something the attorney himself has admitted. He asked for the trial to be postponed but the court denied the request.

In 2015 the Missouri Supreme Court delayed Williams’ execution to allow for further DNA testing, but despite the new evidence it ruled last week that the killing should go ahead. Williams’ legal team is requesting a new hearing or for his sentence to be reduced to life in prison.

The case will now be heard by US Supreme Court judge Neil Gorsuch, who was nominated by Donald Trump in January and serves as the judge for the 8th US Circuit Court of Appeals, which includes Missouri.

Missouri prosecutors say they have enough evidence to show Williams is guilty of murdering Ms Gayle, a former journalist who later moved into voluntary work. They say he sold her laptop after the killing and confessed to the murder to two different people.

These two witnesses formed the core of the case against Williams but his lawyers say the pair – one a cell mate and the other a crack-addicted prostitute who had a relationship with Williams - were motivated by a financial reward offered by Ms Gayle’s family to anyone with information leading to a conviction. Both reportedly received money after the trial.

Williams’ supporters also highlight the racial inequality in the US that means black defendants are much more likely to be sentenced to death than white defendants, especially if the victim is white, as Ms Gayle was.

The pool of possible jurors in Williams’ trial included seven African Americas but all but one were blocked by the prosecution, leaving a jury that consisted of 11 white people and just one black one, despite almost half of St Louis inhabitants being black.