At about 10:30 p.m. on Saturday, a man was withdrawing cash at an ATM on Westheimer near Gessner when he was approached by a gunman who police said tried to rob him.
Investigators said the intended victim also had a gun and shot the would-be robber. He was pronounced dead at the scene.
"We'll contact the District Attorney's Office to see how the district attorney wants to proceed. Whether it'd be referred to a grand jury, which is normally what happens in this type of situation," Lt. Larry Crowson said.
Police said there were several witnesses, and they'll be looking for surveillance footage to determine exactly what happened.