Washington (AFP) - A Texas man is to be executed Wednesday for a double murder he insists he did not commit, in a case that has drawn the attention of the Catholic Church and celebrities Kim Kardashian and Martin Sheen.

Ivan Cantu, 50, who was convicted of the 2000 murders of his cousin and his cousin's fiancee, is one of two inmates scheduled to be put to death by lethal injection in the United States on Wednesday.

The other, convicted serial killer Thomas Creech, 73, is to be executed in Idaho. Creech has been on Death Row for nearly 50 years for killing another inmate.

Cantu's case has drawn widespread attention because of doubts about his guilt.

He was convicted in 2001 of the murders in Dallas the previous year of his cousin, James Mosqueda and Amy Kitchen, Mosqueda's fiancee, who were shot to death.

Cantu's then-fiancee, Amy Boettcher, who has since died, testified at his trial that he had admitted committing the murders and took her to Mosqueda's home later to show her the bodies and look for hidden drugs.

Among the evidence entered at the trial was a pair of jeans with blood from the victims that was found in Cantu's kitchen trash can.

Lawyers for Cantu maintain that Boettcher lied on the witness stand and the jeans, which were too large for Cantu, were planted in the trash can by someone else.

Cantu has steadfastly proclaimed his innocence and said the murders were carried out by a drug dealer to whom Mosqueda owed a substantial sum of money.

A MoveOn.org petition urging Texas Governor Greg Abbott to grant a stay of execution to Cantu has drawn nearly 150,000 signatures.

The Texas Catholic Conference of Bishops has urged that the execution be halted because of "serious uncertainties" surrounding the case.

Among those expressing doubts about Cantu's conviction was the foreman of the jury that presided over his 2001 trial.

Jeff Calhoun, in an article in the Austin American-Statesman, asked for the execution to be delayed pending further investigation.

'Time is running out'

Kardashian, who has been active in prison reform, urged Texas's conviction integrity unit to look into the case. "The time to act to save Ivan Cantu is now!" she said in a post on X.

Sheen, an opponent of the death penalty, made an appeal on Instagram for people to sign the MoveOn petition seeking a stay of execution.

"Ivan was wrongfully convicted of murder more than 20 years ago," the star of "The West Wing" and "Apocalypse Now" said. "Time is running out."

Cantu's lawyers have filed a series of last-minute appeals seeking to halt his execution.

According to a recent Gallup Poll, 53 percent of Americans support the death penalty for someone convicted of murder, the lowest level since 1972.

Capital punishment has been abolished in 23 US states, while the governors of six others -- Arizona, California, Ohio, Oregon, Pennsylvania and Tennessee -- have put a hold on its use.

There has been one execution in the United States this year, that of an Alabama inmate who was the first to be put to death using nitrogen gas.

There were 24 executions in the United States in 2023, all of them carried out by lethal injection.