It happened just before 11:30 p.m. Thursday at the restaurant on S. Gessner near Bellaire Boulevard.
Houston police said the armed man in a mask came inside the restaurant, demanding money and wallets from customers. However, as he was leaving, one of those customers shot the suspect.
As this analysis at Legal Insurrection observes the first eight shots fired either clearly or ambiguously meet the definition of lawful self-defense. The 9th shot to an inert and disarmed person's head did not.
It is still a lawful self-defense until that point.