A murderer convicted 12 years ago in the slaying of an 18-year-old grocery store clerk is asking the state Supreme Court to consider the state of mind of one of his jurors — though she is now dead — after a state appeals court panel turned him down.

Attorneys for Justin Granier, 33, asked state District Judge Jessie LeBlanc last week to halt a Feb. 18 hearing on the alleged statements of juror Gladys Mobley while his appeal is pending before the state’s highest court.

In October 2003, Mobley was on the jury that unanimously convicted Granier of second-degree murder in the slaying of Luke Villar, then a St. Amant High School student.

A high-profile case at the time, Villar was cleaning the parking lot of DeLaune’s Supermarket in St. Amant early Sept. 15, 2001, a Saturday morning, when he was shot in the back twice with a rifle in a bungled robbery attempt.

Granier, one of three convicted for a role in the attempted robbery and slaying, received a mandatory life sentence.

But Granier’s attorneys have raised questions about possible bias from Mobley, who did not disclose during jury selection that her son had worked with Villar until a week before his death or that her son had been questioned by sheriff’s deputies about the slaying.

In April 2013, Mobley admitted to Granier’s investigator, his defense attorneys say, that her son had worked with Villar and said repeatedly during the interview with the investigator that Villar “could have been my son.”

At issue now is whether the investigator, Brad Scott, can testify what Mobley said more than two years ago and overcome general legal prohibitions on hearsay testimony, or second-hand accounts.

In a January 2015 ruling, LeBlanc, of the 23rd Judicial District, found that though Mobley was not asked directly about her son, she had heard prosecutors tell other potential jurors how it was important to disclose family connections to Villar and ordered Mobley to appear in court.

But unknown to lawyers and LeBlanc, Mobley had died the month before. In May, LeBlanc found the “severity of the issues” raised in Granier’s appeal required taking Scott’s testimony.

On Nov. 4, though, a unanimous three-judge panel of the state’s 1st Circuit Court of Appeal overruled LeBlanc. The court found that LeBlanc had erred in allowing Scott’s testimony and ordered the case back to her for further proceedings.

Assistant District Attorney Chuck Long, who tried Granier in 2003, said Friday the effort to consider what Mobley was asked during jury questioning was incorrect and called Scott’s potential testimony “rank hearsay.”

“I’m glad the 1st Circuit saw it our way,” Long said.

Since that ruling, defense attorney Justin Harrell has petitioned the state Supreme Court, arguing the appellate panel abused its discretion and asserted the law has exceptions to the hearsay rule when testimony is tied to someone’s state of mind.

Harrell wrote that under the law, hearsay is limited to facts.

“The facts of Juror Mobley’s April 2013 statement to Mr. Scott is not at issue; her subjective state of mind, her apparent concern and emotional reaction across the span of more than a decade, is,” Harrell wrote.

Despite the unanimous jury verdict against his client, Harrell wrote, a finding of bias from even one juror would require a new trial for Granier.

Mobley refused to sign an affidavit about her statements after the investigator questioned her, Harrell has said in court papers.

Harrell did not return calls seeking comment Thursday and Friday.

Granier has given conflicting statements to investigators about his level of involvement in the attempted robbery and murder, but each placed him at the scene. Granier testified at trial he never got out of the car while Lucas Roddy, who prosecutors say shot Villar, and Josh Barrow went to the store. Roddy was convicted of second-degree murder in 2002 and has a mandatory life sentence. But in a statement to deputies, which Granier later claimed was coerced, he said he was with Roddy, now 34, when Roddy shot Villar.

Barrow, 36, pleaded guilty to attempted armed robbery and being an accessory after the fact to murder and to attempted murder and received a 15-year sentence in January 2004.

Follow David J. Mitchell on Twitter, @NewsieDave.