Jurors took less than an hour Friday to give Ted Kergan the justice he’d been seeking for more than three decades: the conviction of drifter and former French Quarter street clown Ronald Dalton Dunnagan in the 1984 slaying of his older brother and business partner, Crowley businessman Gary Kergan.

“Unanimous! Oh! Kaboom!” Kergan said outside state District Judge Mike Erwin’s courtroom moments after an East Baton Rouge Parish jury of 11 women and one man found Dunnagan, 66, of Bossier City, guilty of second-degree murder, which carries a mandatory sentence of life in prison.

Kergan, who with his brother owned a chain of Sonic Drive-In eateries across south Louisiana, said he was “absolutely ecstatic” when he heard the word he’d been longing to hear for 31 years: guilty.

“It gives me a day off. I don’t have to do this tomorrow. I’ve been doing this for 31 years,” he said of his search for justice.

A backpack that Kergan had in the courtroom contained a framed photograph of his brother, the last known photo of him. Ted Kergan said Gary was his brother by chance but his friend by choice.

“I think he partly reached back from the grave and got him,” Kergan said of his brother.

Dunnagan’s accomplice, former stripper/prostitute-turned-nurse Leila Mulla, pleaded guilty last year to manslaughter in exchange for a 30-year prison term. She was charged with first-degree murder at the time and faced either life in prison or the death penalty if convicted.

Gary Kergan’s son, Wade, was just 9 years old when his father disappeared in late November 1984. His body has never been found.

“I feel relieved. This has been a long time coming. Thirty-one years,” he said outside the 19th Judicial District Courthouse. “The people responsible are where they belong.”

Wade Kergan said he had nothing to say to Dunnagan or Mulla, 50. But Ted Kergan couldn’t resist when asked if he had any parting words for the convicted killers.

“Enjoy the rest of your life at Angola,” he said of Dunnagan, a reference to the Louisiana State Penitentiary. “She’s where she needs to be.”

Mulla, who was living in Astoria, New York, and working as an emergency room nurse when she was arrested in December 2012, is incarcerated in St. Gabriel at the Louisiana Correctional Institute for Women.

“Both of these people were despicable. They contributed nothing to society,” Ted Kergan said.

Mulla testified Thursday that it was Dunnagan’s idea to rob and kill Kergan at Dunnagan’s north Baton Rouge apartment on Nov. 29, 1984. After she and Kergan had sex, she said she gave him wine that Dunnagan poisoned. Mulla said Dunnagan, who was hiding in a closet, smothered Kergan, dismembered his body in a bathtub and disposed of it in garbage dumpsters.

Kergan was declared legally dead by the courts in 1986.

A large amount of Gary Kergan’s blood was found in the trunk of his abandoned car in Metairie just days after his disappearance, but it was not until 2012 that DNA testing — unavailable years before — confirmed it was Kergan’s blood.

“He skated for the last 31 years because he did a very thorough job of disposing of Gary Kergan’s body. Time is up. Science caught up with him,” prosecutor Dana Cummings told jurors before they began deliberating.

Cummings reminded the jury of Mulla’s journal that was discovered inside a lock box in a Las Vegas apartment about a week after Kergan’s disappearance. Dunnagan had fled to Las Vegas after the killing. The diary contained entries from mid-November 1984 that indicated she and Dunnagan planned and even practiced Kergan’s robbery and murder.

Police have said Kergan was wearing jewelry and carrying more than $2,000 in cash when he disappeared.

Cummings acknowledged to the jury that Mulla is no saint.

Dunnagan’s court-appointed attorney, Susan Hebert, countered that prosecutors made a deal with the devil and said Mulla told prosecutors whatever they wanted to hear.

Hebert said after court that Dunnagan, in December, turned down the same deal that Mulla had accepted.

He will be sentenced Oct. 7.

“I wish we could do more for the (Kergan) family. I wish we could give them back Gary’s body,” Cummings told reporters. “This is the best we can do. It’s a long time coming. It’s not quite enough.”