A 25-year-old man was shot and killed at a south-side Walmart Tuesday night, Tucson police say.

The shooting happened about 9:30 p.m. in the parking lot of the store at 1650 W. Valencia Road, said Sgt. Maria Hawke, a Tucson police spokeswoman in a news release.

When officers arrived, they found Jeremy Wagner on the ground with at least one gunshot wound, the release said. The man died at the scene.

Witnesses reported seeing two groups of people arguing and fighting in the eastern part of the parking lot just before the shooting, the release said. The suspected gunman ran away after the shooting, heading east on Midvale Park Road.

A 20-year-old man was apprehended by a security guard at a nearby apartment complex.

Police interviewed the man and some witnesses, but no arrests have been made.