On the eve of Seth Fontenot’s murder trial, the presiding judge barred prosecutors from using evidence of Fontenot’s alleged illegal sales of the prescription drug Adderall.

Judge Ed Rubin on Monday said no to bringing in the drug allegations after he learned the matter had been ruled out by fellow 15th District Judge Kristian Earles at a hearing in November 2013.

Fontenot, 20, killed 15-year-old Austin Rivault and injured two other teens on Feb. 10, 2013, by firing three hollow point 9 mm rounds into a truck the boys were in. He told detectives he shot at the taillights of the truck to scare the boys and said he believed they had just broken into his truck and were fleeing the scene of a burglary.

Assistant District Attorney J.N. Prather filed papers Friday asking to use an interview Fontenot had with a detective after the killing. Asked by Lafayette Police Detective Jason Migues why he believed his truck had been broken into multiple times, Fontenot said it was probably because he stored his Adderall in his truck.

Rubin sided with Fontenot’s attorneys, Thomas Guilbeau and Katherine Guillot, who argued Monday that the District Attorney’s Office tried and failed over a year and a half ago to use the same evidence at Fontenot’s trial.

Guillot said Earles in November 2013 wholeheartedly ruled that Fontenot’s links to illegal drug sales were overly prejudicial and not vital to the murder trial. Rubin took over the Fontenot case in January 2014 when Earles transferred to the court in Acadia Parish, which with the parishes of Lafayette and Vermilion make up the 15th Judicial District.

Guillot was referring to a contentious Nov. 13, 2013, hearing where Earles denied allowing alleged drug-dealing allegations into the trial but sided with Prather and former Assistant District Attorney Mark Garber when he ruled Fontenot’s racially tinged cellphone texts could be used to bolster prosecutors’ case against Fontenot.

Garber, who was lead prosecutor in the Fontenot case, has since left the District Attorney’s Office. He recently announced his candidacy for Lafayette Parish sheriff.

Lafayette police were called to the Green Meadow Road home that Fontenot shared with his family several times prior to the February 2013 killing. Police investigated break-ins to Fontenot’s truck and his mother’s vehicle.

Arguing the drug evidence was admissible, Prather on Monday hinted that Fontenot came out of his house firing his pistol because he wanted to protect the drugs he kept inside his 2007 Chevrolet Avalanche.

“We have a homicide. We have somebody who went out and shot somebody. Why?” Prather said. “We’re looking at the state of mind of the defendant at the time of the commission of the homicide.”

Despite Prather’s argument, Rubin decided to go with Earles’ decision and keep the drug dealing out of the murder trial. However, Fontenot still faces a trial on drug distribution, charges that were filed in the aftermath of Rivault’s death. The case has lain dormant pending the outcome of the murder trial that begins Tuesday with jury selection.

Fontenot faces life in prison if 10 of the 12 jurors find him guilty of first-degree murder. Even if the jury finds him guilty of second-degree murder, it still means Fontenot would spend the rest of his life in prison, with no chance of parole.

Jurors also could vote to convict Fontenot of manslaughter, which brings a punishment of up to 40 years in prison at hard labor, depending on what the judge will order.

Fontenot on Oct. 31 offered to plead guilty to negligent homicide, which calls for a maximum prison sentence of five years. The District Attorney’s Office declined the deal.