Lt. J.P. Horelica said the two brothers were walking across the parking lot at the Cortland Med Center apartment complex in the 9100 block of Lakes at 610 Drive around 8:40 p.m.
A car allegedly pulled up to the teenagers before someone jumped out and shot at them. Horelica said the 13-year-old died at the scene, and the 18-year-old was transported to the hospital, where he is expected to survive.
HPD said there's no indication at this time that the shooting was gang-related, although it is still early in the investigation. It is unclear whether it was a random incident or if the victims were targeted.
According to investigators, the teen boys lived at the apartment complex. Their parents were at the scene but did not witness the incident.
Houston police said the suspects fled in what appeared to be a gray vehicle, possibly a Lexus. One of them was allegedly wearing a blue hoodie.
Anyone with information is urged to contact the HPD Homicide Division at 713-308-3600 or speak anonymously with Crime Stoppers at 713-222-TIPS.
HPD initially reported the second victim's age as 16 but later corrected it to 18. This story has been updated to reflect that change.
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