ST. PETERSBURG — Keith Evans still can't sort out how an argument between his neighbors escalated so quickly and ended in one of them being killed.

"Both of those guys are my friends," said Evans, 53.

It happened about 7:30 p.m. Sunday. Police said 25-year-old William Porter Headlee was having a conversation on the sidewalk near Lonnie Lee's apartment door, apparently too loud for Lee's taste.

Lee went outside to ask Headlee to quiet down. The request sparked an argument, and Lee, 34, told police the younger man shoved him — an assertion not backed up by a witness.

The witness told police that Lee punched Headlee and, as he lay on the ground, pulled out a gun and shot him twice.

Evans is puzzled, as he said neither man seemed the violent type.

Evans lived below Headlee at the Gateway Apartments, a group of pink stucco buildings with about 200 units at 2000 Gandy Blvd. N. Lee lived next door to him.

"Something really ticked that man off," Evans said.

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Neither man has a criminal record in Florida.

Lee works at Goodwill Industries, and his girlfriend and young child had recently moved into his apartment, Evans said.

"He was a really quiet family guy," Evans said. "Lonnie didn't bother anybody."

Headlee moved to St. Petersburg eight months ago from Kennesaw, Ga., a suburb of Atlanta. His family said he was talkative and friendly.

They can't figure out why something like this would happen.

"Everybody loved Porter," his father, Tom Headlee, said.

Those traits made him a good salesman. He worked for Home Performance Alliance, a door and window sales company.

"He never gave up," Tom Headlee said. "He had that fortitude to always get a better job and keep going forward."

A few weeks ago, Headlee called his mother to ask for her meatloaf recipe. He added mashed potatoes and green peas to the menu and invited over a few neighbors, including Evans.

"He was giving everybody some," Evans said. "Whoever wanted some."

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Headlee's family plans to drive from Georgia to St. Petersburg next week to collect his things.

Initial police reports indicated that Headlee and Lee argued over loud music, but police said later that a loud conversation sparked Lee's anger.

The Headlees don't see a difference. It's still a senseless crime.

"You don't murder someone," Tom Headlee said. "That can never be justified, to kill someone over something like that."

Headlee told his parents he liked living at Gateway. He wouldn't take their offer of money to help him move out.

"He was never scared of anybody there," his sister, Rachel Headlee, said.

Since January, police have responded to Gateway 109 times. Call sheets list noise complaints, brawls and Baker Act requests.

"Strangely enough, I knew it was inevitable that something like that would happen," said Joel Barber, 57, who lives in the building across from Evans.

Over the past several weeks, Evans said, Lee had increasingly complained about noise. Evans asked his visitors to quiet down. And he noted that Headlee, who lived above and to the left of Lee, could be loud when he drank alcohol, as he was Sunday night.

"Two lives," Evans said. "Wasted.

Times researcher Natalie Watson contributed to this report. Claire Wiseman can be reached at cwiseman@tampabay.com or (727) 893-8804. Follow her on Twitter @clairelwiseman.