JOHN YANG: Nine times since 2015, Richard Glossip has had a date with death days when he was scheduled to be executed in the Oklahoma State Penitentiary by lethal injection, and nine times the courts have delayed his execution, so legal challenges could be considered.

Now he's asking if the Supreme Court to throw out his 2004 murder conviction and give him a new trial.

And this time he's supported by Oklahoma's chief law enforcement officer, Attorney General getting her Drummond.

Drummond says that the prosecution Glossip's trial acted improperly, including withholding evidence from the defense and allowing a key witness to lie.

Throw that evidence out Drummond says and there's not enough to convict Glossip much less sensitive to death.

Adam Kemp is one of our community's reporters He's based in Oklahoma City.

Adam, who is Richard Glossip and how did he get here?

ADAM KEMP: Right.

In 1997, Glossip was the manager of a motel that was owned by Barry Van Treese the murder victim in this case.

He was convicted of a murder for hire plot that Justin Sneed carried out he said he was paid $10,000 by Glossip to murder Van Treese.

Since then, it's been more than 25 years of Glossip on death row with as you documented nine different execution dates and three last meals actually for Glossop.

He had his original conviction overturned by the Court of Criminal Appeals here in Oklahoma.

And then in 2004 was convicted again by a different jury.

Since 2014, Glossip has had several execution dates that have come and gone two different times his case has actually reached the Supreme Court.

JOHN YANG: And it's a 2004 retrial that's the subject of all this.

And as recently as January the Attorney General filed a brief with the Supreme Court opposing Glossip.

But now he's switched.

What happened?

They're concerned about the key witness who testified in that 2004 case.

ADAM KEMP: That's right, John.

After Oklahoma lawmakers actually called for an independent investigation into the prosecution of Richard Glossip, several different concerns came to the forefront about Justin Sneed, the state's main star witness that included, you know, some testimony from other inmates who were with Sneed.

They said he confessed to doing the murder by himself.

Those interviews with those inmates were withheld from the jury trial.

There was also concern about Sneed's mental health that he had an undisclosed mental illness that was also kept from the juries.

On top of all that, there was a memo that was found in the DA's office that detailed how prosecutors were feeding Sneed information before he would testify.

JOHN YANG: Now, in addition to the Attorney General of Oklahoma was getting support from the Innocence Project and also support from some legal scholars.

Is there anyone opposing him?

ADAM KEMP: Yeah, the Van Treese family themselves has been very vocal against Glossip.

And it has said that, you know, they've filed a friend of the court brief with the Supreme Court to have his conviction upheld.

The Van Treese's son, Derek Van Treese has actually said that he believes Attorney General Drummond has overstepped his bounds in the role here saying that the Oklahoma Court of Appeals has already ruled on this and they have chosen to upheld Glossips conviction.

On top of all that, Governor Kevin Stitt has said that he will not intervene on behalf of Glossip and is just waiting to see how this all plays out.

JOHN YANG: You know, once the Glossip lost his case at the state Supreme Court, the Attorney General went to the state Clemency Board asking for clemency for Glossip and lost there as well.

Now since the death penalty was reinstated, Oklahoma has carried out more death sentences per capita than any other state.

Could this case change the way politicians look at the death penalty?

ADAM KEMP: Yeah, it's been a really fascinating look here at lawmakers.

Choices since this Glossip case has reached the Supreme Court again, there has been kind of a groundswell of support, not only to make sure that these death row cases are being looked at, but some Oklahoma State lawmakers are even Glossip's top champions.

They've come out to really rally for support for him and say that he deserves a new trial.

There's been different groups formed.

Oklahoma lawmakers concern for the death penalty that is mainly backed by Republicans to not only look at this Glossip case, but at other death row cases they believe maybe we're not prosecuted fairly.

JOHN YANG: You know, we're going to probably going to hear whether the Supreme Court takes his case early this fall.

What happens if the Supreme Court says no, we're not going to intervene here?

ADAM KEMP: Right, that would put Glossip on track to have that 10th and what we hear is most likely final execution date.

As he's been to the Supreme Court twice now many law experts believe this is his final chance at possibly getting a new trial JOHN YANG: Communities reporter Adam Kim, thank you very much.