Jarvis Smith and his cousin Lee Edward Jones had been arguing about Jones' dog.

PAHOKEE — Jarvis Smith was running for his life Friday morning when his cousin lifted a long rifle and fired a single, fatal shot into the back of his head, relatives told Palm Beach County Sheriff's Office authorities.

Their relatives had seen the cousins' dispute escalate from an argument in Smith's mother's Pahokee home to a brawl on the road outside. They said they'd separated the two shortly before 8:30 a.m. But 20-year-old Lee Edward Jones was still mad, he told sheriff's investigators.

He grabbed the .22-caliber long rifle he'd dropped outside his aunt's home on Royal Palm Court and chased his cousin. Smith, 32, tried to get into a relative's car but she screamed for him not to. Her baby was inside.

Smith kept running. Jones fired a shot. Smith fell.

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Jones was detained about two blocks from the shooting by a deputy who noticed that his red shorts matched the description of the gunman that multiple people had given to 911 dispatchers. When the deputy asked what he was doing, Jones said he had shot his cousin, according to his arrest report.

Jones is being held in the Palm Beach County Jail on charges of first-degree murder and possession of a weapon as a convicted felon without the possibility of posting bail.

Smith, 32, died almost immediately, Palm Beach County Fire Rescue crews said.

Relatives told sheriff's investigators that Smith and Jones had been fighting about Jones' dog. Jones told investigators Smith had taken his dog and when he saw Smith's car parked outside his aunt's that morning, he decided to stop and confront Smith.

He had a long rifle with him — he was going rabbit hunting, he said — that he left outside the house. Smith's mother told the cousins, who shared a home near hers, to take their argument elsewhere, so the men went into the road and started to fight.

Smith's mother, another relative who had been driving by and a neighbor broke the men up.

But Jones ran back to his aunt's house, picked up the rifle and chased Smith, then fired a shot.

Jones kept running and dropped the rifle in an abandoned home in the area. He was detained nearby. When detectives interviewed him about what had happened, he said he didn't realize the shot had killed his cousin.

State prison records show that Jones was convicted of burglary in Palm Beach County on Sept. 6 for a car break-in the month earlier and was sentenced to two years of felony probation. He is scheduled to remain on probation through Sept. 5, 2020.