A growing list of celebrities and a bipartisan group of Texas lawmakers are the latest to call on Governor Greg Abbott to halt the execution of a death row inmate amid what the lawmakers call a "cloud of doubt surrounding his guilt." Rodney Reed, who maintains his innocence in the 1996 murder of Stacey Stites, has garnered high-profile supporters including "Dr. Phil" McGraw and Kim Kardashian West, who tweeted at Abbott to "do the right thing."

With his November 20 execution date looming, celebrities including Rihanna, T.I., Meek Mill, Questlove, Gigi Hadid, Busta Rhymes, Pusha T, Seth Green and Janelle Monáe have also offered their support, with their social media callouts helping fuel an online petition for clemency that's garnered more than one million signatures.

I just signed this petition to tell @GovAbbott to stop the execution of Rodney Reed. You can too! #FreeRodneyReed https://t.co/ELQ3MYq1RG — Gigi Hadid (@GiGiHadid) November 4, 2019

On Tuesday, 26 state lawmakers —13 Republicans and 13 Democrats — including all 12 members of the bipartisan Texas House Criminal Justice Reform Caucus sent a letter imploring Abbott to give Reed a reprieve to allow time for new developments in the case to be explored. They say the case against Reed "has been called into serious question by compelling new witness statements and forensic evidence along with evidentiary gaps that could be filled with additional investigation and testing."

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Executing Reed "without certainty about his guilt" may "erode public trust — not only in capital punishment, but in Texas justice itself," said the letter, which was also sent to the Texas Board of Pardons and Paroles.

Reed, who is black, was found guilty of raping and killing Stites, a white woman who was 19 years old at the time.

Reed, now 51, was arrested after his sperm was found inside Stites' body. He pleaded not guilty, and in 1998, he was convicted of murder and sentenced to death by an all-white jury.

Reed initially said he didn't know Stites, but later said he was having an affair with her and that they had consensual sex the day before her death. But he has long maintained he did not kill her.

Police had Reed's DNA available for testing from a separate sexual assault investigation, according to a 2018 prosecution motion asking to dismiss one of Reed's appeals. Reed had faced a series of sexual assault allegations, but was acquitted in the only case prosecuted, according to a request for a sentence commutation filed last week with the Texas Board of Pardons and Paroles.

At Reed's murder trial, prosecutors maintained Stites had spent an evening at home with her fiancé before leaving to drive herself to work in his truck around 3 a.m.

They said Reed intercepted her somewhere between 3 and 5 a.m., raped and strangled her and left her body in a remote area in Bastrop.

Experts called by the prosecution said she'd been raped just before her murder, claiming sperm could not have survived from 24 hours earlier. But in the commutation request, Reed's defense attorneys argue the state relied on inaccurate science.

They cite forensic experts who say that the small amount of sperm found in Stites' body supported Reed's story that he had had consensual sex with Stites the day before her murder, and that sperm could survive up to 72 hours in the body after sex. The medical examiner whose trial testimony had bolstered the state's timeline later changed his account, according to the commutation request, saying there was no evidence to indicate the presence of Reed's sperm in Stites' body was the result of a sexual assault.

The defense experts cited in the commutation request also said the state of Stites' body indicated she was killed before midnight — when she would have been at home alone with her fiancé, Jimmy Fennell. In addition, the defense has offered several new witness accounts they say cast suspicion on Fennell, a white former police officer who would later serve 10 years in prison for kidnapping and having improper sexual contact with a woman he had taken into custody in 2007.

Jimmy Fennell CBS Austin

The latest witness to speak in Reed's defense, an inmate who was incarcerated with Fennell at a Texas prison, recounted in an affidavit submitted to the parole board that Fennell confessed to killing Stites during a 2010 conversation in jail. According an affidavit submitted by the witness, a former leader in a white supremacist prison gang, Fennell said his ex-fiancée was "sleeping around with a black man behind his back" and confessed, "I had to kill my n----r-loving fiancée.'"

Fennell denies any involvement in the slaying and was devastated by Stites' death, his lawyer, Bob Phillips, told CBS News. Phillips dismissed the accounts of the new witnesses, questioning why they had waited so long to come forward, and said there was "not a scintilla of merit" to the inmate's account.

"This is coming from a career criminal who has pending cases in Hays County," Phillips said. "It's classic Hail Mary stuff from a guy who's trying to save his own scalp, I'm quite confident."

Phillips said Reed's claim that he was having an affair with Stites was "absolutely untrue" and said Reed's legal team was trying the case in the court of public opinion "at the 11th hour" because no court has so far upheld their appeals.

A stay of execution was denied last week by the Texas Court of Criminal Appeals, and the same court in April 2017 turned down Reed's efforts to seek DNA testing on additional items found at the crime scene, including the belt used to strangle Stites. The court said any new testing results would have no effect to undermine the state's timeline of events or support Reed's claim of a consensual relationship, and even with the "overly expansive presumption" the tests would find Fennell's DNA, "the jury would most likely not be surprised to learn that Fennell's profile was found on his own truck or on items found in his truck." The court also said the items have likely been contaminated over the years.

The U.S. Supreme Court declined to hear Reed's appeal of the DNA issue and he is now seeking the tests via a civil rights lawsuit.

In the commutation request, Reed's lawyers asked the state parole board to recommend Abbott commute Reed's sentence from death to life in prison. His defense attorneys said Reed is not asking for a pardon "because he wishes to have his conviction overturned in court and to be vindicated at a fair trial in which a jury of his peers considers all of the evidence he now presents to this Board."

"Especially in light of the new evidence that has continued to emerge, a commutation to a life sentence is necessary to ensure that Mr. Reed is not executed in error," his attorneys said.

The Texas Attorney General's office, which handled the case on appeal, and the Abbott's office did not respond to requests for comment.