Two armed robbers picked the wrong victim in northwest Dallas.
Police said they approached a man eating his dinner in the parking lot of Whataburger at Inwood Road and Lemmon Avenue and tried to rob him around 1 a.m.Thursday morning.
The man was an off-duty, but armed security guard. He shot and killed one of the robbers. The other ran away.
Police have since detained a man who is possibly the second suspect. He is being questioned by investigators.