A man was fatally shot in Houston. Hours later, a boy thought to be his son was found dead in an SUV.

A suspect was arrested in the deaths of a man who was fatally shot Tuesday and a toddler, thought to be the victim's son, who was found dead in the back seat of an SUV, Houston authorities said.

The Houston Police Department said Wednesday afternoon that the 38-year-old man, identified only as a person of interest who had been questioned in the incident, was accused of murder and tampering with evidence.

On Tuesday night, the department released security video that it said showed the gunman.

Investigators were trying to determine a motive, Houston Executive Assistant Police Chief Larry Satterwhite told reporters.

The boy’s apparent father, 38, was found dead near a strip mall southwest of downtown Houston after authorities responded to a report of a shooting at 1:46 p.m., Satterwhite said.

The victim hasn’t been identified.

Investigators determined that after the gunman and the victim met up, an argument may have followed and the gunman opened fire, shooting the man multiple times and driving away in the victim's SUV, Satterwhite said.

Five hours later, as authorities were investigating the shooting, a woman called police and reported that her husband and her 2-year-old son were missing, Satterwhite said.

Authorities quickly determined that the missing husband and the shooting victim were the same person, Satterwhite said.

"We didn't know about the child until she called at 6:36," he added.

Within 30 minutes, Satterwhite said, officers found the abandoned SUV about a mile away from the original scene. The toddler was in the back seat, unresponsive, he said.

Officers broke the vehicle's window, began administering CPR and called for an ambulance, Satterwhite said.

"Sadly, it was too late," he said. "The child had passed in the car."

The boy's cause of death was unclear, although Satterwhite said he may have died of heat exhaustion. It wasn't clear how long the SUV had been left there.

"Pray for this family," Satterwhite said. "A mother lost her husband, and she lost her 2-year-old child today."

This article was originally published on NBCNews.com