SAN ANTONIO -- The San Antonio Police Department told KENS 5 a man who put himself in the middle of an argument in the parking lot of an apartment complex is wanted for murder.

When the argument got heated, police said the suspect shot and killed a man.

The incident started around 8:30 p.m. with an assault call from the 1300 block of Rigsby Avenue.

By the time police arrived at the scene, they found the victim with a gunshot wound to the chest.

The 29-year-old victim did not survive. He was reportedly found next to his girlfriend's vehicle.

Investigators said he and his girlfriend had been arguing. The shooter who is a stranger intervened.

The victim and unknown gunman started arguing. Police said the gunman pulled out a gun and fired twice. One of the shots killed the victim.

The murder victim's identity has not been released. Investigators say he lived at the complex with his girlfriend.