Walter Owens brought a gun to a fistfight that started over $5 in gas money. For reasons that aren't entirely clear, he shot four times into a St. Petersburg crowd that was watching the fight.

The effects were devastating: One of Owens' bullets killed Tremel Mitchell, 22, who was standing outside his grandmother's house and had nothing to do with the dispute.

On Thursday, a jury found Owens guilty of second-degree murder for the 2010 crime, which Assistant State Attorney Thomas Koskinas called "a senseless, ridiculous act over a ridiculous issue."

Mitchell's father Terral Smith, 49, who drove from Atlanta just in time for the verdict, said the dispute between the other men "should have ended in a fistfight," not in the death of his son. He recalled picking out a suit for his son to be dressed in for the funeral viewing and said that wasn't right.

"He should have been picking one out for me," Smith said.

Mitchell's mother, Vanessa Mitchell, said she didn't hear about the $5 gas dispute until after her son's death, and said she still doesn't know too much about it.

"All I know is that I lost a child," she said. "I can't believe my son died over $5."

Pinellas-Pasco Circuit Judge Philip Federico sentenced Owens, 27, to life in prison. Prosecutors said that sentence was mandatory because Owens committed the murder less than three years after getting out of prison.

The trial this week took a brief and unusual turn when defense attorney Christie Pardo called a St. Petersburg police-officer-turned-prison-inmate as a witness. Anthony Foster, once the detective on the case, later pleaded guilty to wire fraud in a scheme to extort cash and gifts from a police informer. He answered basic questions about the case and came to court wearing a dress shirt, slacks and tie, instead of prison garb — but, like other inmates, no belt.

Prosecutors said the 2010 dispute began between a man named Kevin Valentine, who wanted another named Jonathan Smith to drive him somewhere to buy marijuana. Smith reportedly said yes, but wanted $5 in gas money that never got paid.

This led to an ongoing dispute and a plan for a fistfight. Valentine went to fight Smith on 20th Avenue S. Though Valentine initially told investigators that Owens came along to back him in the fight, he testified at trial that Owens wasn't even there.

But three eyewitnesses placed Owens at the scene.

The scene was 4651 20th Ave. S, home to Gertice "Mae" Mitchell, Mitchell's grandmother. It wasn't unusual for a group of Mitchell's friends to gather there, she said Thursday. They came around after he got off his 2-11 p.m. shift at Walmart. She didn't mind them hanging outside. If they got too loud she would flick the outside lights, and they would call out "all right Grandma" and settle down.

But one night in May 2010, she flicked the lights and the noise didn't stop. She went outside, and that's when the fight was beginning. Tremel Mitchell was outside, too.

At some point after the fight began, witnesses said, Owens fired four times.

People in the crowd yelled "gun" and scattered. Tremel Mitchell turned around and was rushing to get back inside his grandmother's house. His grandmother was just in front of him. She made it in, but he didn't.

Tremel Mitchell fell, and "he said 'Grandma!' " she recalled Thursday afternoon. The shooting was so close, "I could have gotten hit, too," she said.

The trial was emotional for her and other relatives. She said Mitchell was a hard worker who enjoyed his job at Walmart.

Mitchell's mother said Walmart employees came to his funeral and the store paid for the food. Even now, when she goes to the store, other workers tell her they miss him, she said.

Other friends come by her house, sometimes just to do the things her son used to do — like watching the Buccaneers on television.

Tremel Mitchell died before the birth of his daughter, who is now 2 years old.

After the verdict was read on Thursday, with Owens still in the courtroom, Tremel Mitchell's aunt Rosalind Fletcher stood and said "for God to forgive us, we have to forgive you." And she said they did.

Vanessa Mitchell said it was very sad to see another family — Owens' family — losing a loved one. "I pity for him," she said. But, she pointed out, she has lost her son forever.

"Justice was served," she said.

Curtis Krueger can be reached at ckrueger@tampabay.com or (727) 893-8232.