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A St. Tammany Parish jury Friday night found 24-year-old Devin Baham guilty of manslaughter, aggravated arson and obstruction of justice in the stabbing death of Ashley King in 2012.

The verdict was unanimous on all counts.

The jury returned the verdict at 10:35 p.m., according to Lisa Page, spokeswoman for 22nd Judicial District Attorney Warren Montgomery. The jury had begun deliberating at about 6:15 p.m. after a four-day trial.

Baham had been charged with second-degree murder, but the jury found him guilty of manslaughter — the same reduced charge that Andrew Sumner, who testified against him, pleaded guilty to in March in a plea deal.

“I want to thank the jury for their time and attention in this very difficult case,’’ Montgomery said in a written statement. “I believe justice has been served for the victim and her family by the jury’s unanimous verdict.”

Baham had taken the stand in his own defense Friday, telling a story of brotherhood and betrayal on the final day of his trial. He testified that he had never met Ashley King, the woman he was accused of stabbing to death in 2012, and never set foot inside the Slidell apartment prosecutors say he set ablaze to hide his crime.

Instead, he said that Sumner, once as close to him as a brother, killed the woman who been Sumner’s drug dealer for his Oxycotin habit and then, with the collusion of Sumner’s pregnant girlfriend, Katelyn Lusich, set up Baham to take the fall.

Baham’s performance contrasted sharply with that of Sumner, who looked down and fidgeted on the stand Wednesday and Thursday, and was often told by the judge to speak up.

Baham, 24, spoke audibly and firmly, making eye contact with his lawyers and the jury.

The two men’s demeanors were not the only things that clashed.

In Sumner’s version of the crime, the two men went together to King’s apartment twice, on Feb. 22 when she was killed and on Feb. 23 when her apartment was torched. But Sumner, 22, painted Baham as the one who wielded the knife that wounded King 13 times while Sumner cowered in the kitchen.

Baham also was the one who orchestrated the cover-up, Sumner said, testifying that his friend stayed behind to clean up while he and Lusich left. That included cutting the dead woman’s fingernails and soaking her fingers in some kind of chemical in an effort to eliminate DNA.

But Baham told a far different story, portraying himself as an innocent stooge who spent more than two days with Sumner without realizing that he had committed a heinous crime or catching on that Baham was being set up for the fall.

Baham said he didn’t go with Sumner to buy pills from King because he didn’t take “roxies,” a street name for Oxycontin. He also wanted to avoid illegal activity because he was on probation for previous theft convictions, he said.

He said Sumner dropped him off Feb. 22 at Heritage Park, near King’s Bayou Lane apartment, where he spent hours playing football with strangers until Sumner finally picked him up.

Then, he said, the duplicity began, with Sumner suggesting a fishing trip that weekend in order to get his help in collecting several containers of gasoline at Sumner’s house — fuel that would be used to set the fire.

Later, he said, Sumner got him to help him clean Lusich’s car by saying the couple wanted to trade the two-door Nissan Altima coupe in for a four-door Maxima because they were expecting a baby.

Baham said his suspicions were aroused the day of the fire when Sumner returned after a mysterious early morning errand and Baham heard firetruck sirens and saw smoke rising from the apartments across the bayou. “I asked, ‘Is that your work?’ ” Baham testified. But Sumner, who smelled of gasoline, denied it, he said.

When police came to his family’s home in Huntwyck Village in Slidell, Baham said, he thought they suspected him of some burglaries in the neighborhood and was shocked when they told him he was under arrest for first-degree murder and aggravated arson.

Baham testified that Sumner had communicated with him while both were in the St. Tammany Parish Jail awaiting trial and offered to pay him $300,000 to take the rap.

Both the prosecution and the defense tried to capitalize on the contrast in demeanor between the two men.

Assistant District Attorney Jay Adair, in closing arguments, described Sumner as a skinny and geeky kid who looked on the older and stronger Baham as his big brother. He was along for the ride, trying to please Baham, Adair said.

“Andrew Sumner was rich, spoiled, submissive, a beta male if you will, someone who’s used to taking orders, not giving them,’’ he said as he showed the jury pictures of the two, including a picture taken after his arrest in which Baham was smiling.

Adair and fellow Assistant District Attorney Julie Knight made much of that smile, which Adair described as smirking and arrogant. He pounced on Baham’s testimony that he had been joking with police who had made him take off his shirt for a picture, saying humor was “my sword and shield.’’

A sword is an instrument of aggression, Adair said. “That’s what an alpha male talks about, someone used to giving orders. ... Look at him, that’s Ashley’s killer, right there.’’

Defense attorney Martin Regan, on the other hand, said Sumner “squirmed and wormed” on the stand. “He wouldn’t look at you. He wouldn’t speak up. ... I’d give him an F for truthfulness.”

Regan repeatedly stressed that Sumner and Lusich, who have since married and had a child, have an enormous stake in helping the prosecution convict Baham because of earlier plea agreements they had reached.

Regan pointed out that Sumner has not yet been sentenced for the counts of manslaughter, aggravated arson and obstruction of justice to which he pleaded guilty. “The state doesn’t trust him,” he said. “If the state doesn’t trust him to tell the truth, you shouldn’t either.”

Follow Sara Pagones on Twitter, @spagonesadvocat.