A Jefferson Parish jury found Tory Clark guilty of second-degree murder Friday, handing down a verdict that will send the 20-year-old to jail for at least 35 years for the shooting death of Terrance Augustine near a Kenner block party in 2010.

Clark, who was 15 at the time, could have been convicted of a lesser charge of manslaughter or negligent homicide, or he could have been found not guilty had the jury decided he was acting in self-defense.

Jurors, however, sided with prosecutors, taking 90 minutes to deliver a verdict that left the family of the slain teenager stoic as Clark’s family choked back tears, his mother burying her tear-streaked face in her hands.

All were under strict orders from 24th Judicial District Judge Ray Steib to show no emotion when the verdict was read. The last of the 12 jurors to file out of the courtroom sobbed as she left.

Defense attorney Rachel Yazbeck said she will file an appeal. Clark will be sentenced March 17.

Second-degree murder typically carries a sentence of mandatory life in prison with no chance for parole, probation or suspended sentence. However, because Clark was 15 when he committed the crime, the mandatory minimum without parole is 35 years, with any additional time up to the discretion of the judge.

Prosecutors say Charles Lathers, who was also 15 in 2010, was firing a gun alongside Clark, and they plan to try him for second-degree murder in a separate trial.

Clark’s defense rested on his contention that another teenager shot at him first after two groups of youths briefly exchanged words at a block party on Greenwood Street in Kenner before heading down to 27th Street, where the shooting took place.

Assistant District Attorneys Matt Clauss and Shannon Swaim, however, argued that the lack of any bullets, shell casings or damage from gunfire indicating anyone other than Clark and Lathers was involved showed there were no other shooters.

Further, they noted that only Clark and one other witness — with whom they said Clark could have collaborated before his confession — ever told investigators they heard someone else shoot. Only after they gave statements to the police, prosecutors said, did witnesses begin to say Clark didn’t shoot first.

Many witnesses testified reluctantly. Corey Cage, a cousin of Clark’s called by the prosecution to talk about the statement he gave to police, replied to prosecutors’ questions repeatedly with variations on “It’s been a long time. I can’t really remember.”

What was generally agreed was that Jade Berry, who testified at the trial, went to one of Clark’s friends at the party, Danny Bell, and told him another boy, Dorian Johnson, had dragged her along the ground by her hands, scraping her knees until they bled.

Bell told his friend Cage, and the two led a group to find Johnson and his friends. The two groups passed each other briefly, and the boys being sought left the party, which was winding down.

Clark’s group followed and, according to testimony from Clark and others, Clark grabbed a gun he had hidden in an alley. When they got to 27th Street, about a dozen shots were fired, and Terrance Augustine, who was on his way to the party with his cousins Patrick and Lorenzo Augustine, fell to the ground with bullet holes in the back of his head, through his lip and in his back.

He died early the next morning in the hospital.

Clark told police that Keeven Robinson, a boy from the other group, had a revolver in his belt earlier that night and was the one to fire first. Clark said he shot four times. At the trial, though, he said his head was turned away while he pulled the trigger and that the gun might have jammed. Another defense witness, Brennen Bellard, said he didn’t think Clark’s gun ever fired.

Under questioning by Swaim, however, the prosecution highlighted apparent inconsistencies in their testimony, including the fact that Clark initially said it was Robinson who shot but later said it could have been another boy who was with him, Letyres Turley.

In closing arguments, Clauss said the jury need only find that Clark fired his weapon with intent to harm or kill, regardless of who it was, and that as part of the aggressor group he could not claim self-defense.

He reminded jurors that Augustine’s parents would never see him again and that the trial was not about whatever promise Clark may have shown on the basketball court or the classroom.

“We’re here because of what Tory Clark did, and what he did was commit second-degree murder,” he said.

Swaim sounded a similar note in her closing argument, saying the decision to fire the gun brought tragic circumstances for both boys’ families.

“We should not be here,” she told jurors while arguing for a conviction. “But we’re here because of Mr. Clark. We’re here for a decision that changed his life, but it took another life. It’s horrible that this is his lesson, but it has to be ... and you are the ones that have to do it.”

Follow Chad Calder on Twitter, @Chad_Calder.