It happened at a smoke shop called Northside 420 in the 11900 block of the Eastex Freeway near Winfield.
Police say the gunman walked into the store and pointed a gun at the clerk, demanding cash. But the clerk turned the tables on the robber and pulled out his own gun and fired multiple times at the suspect.
The suspect stumbled out of the store and collapsed in the parking lot.
"He came out of the store and he fell out right there in the parking lot," said Sgt. Felipe Rivera with the Harris County Sheriff's Office. "At this time, I don't know how many times he was struck, although we know there were multiple shots."
When deputies found the suspect's body, he still had what they say was a pellet gun.
The clerk was not injured in the shooting.
A grand jury will decide whether the clerk should face charges.
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