The shooting happened Sunday afternoon around 4:20 p.m. at a house in the 400 block of Beech Street.
Police say they were responding to a call of man being shot and several people fleeing the scene.
When police arrived, they confirmed one person had died on scene.
About an hour after the shooting, another person arrived at a nearby hospital with gunshot wounds. That victim also died from their injuries, police say.
A third person arrived at HCA Houston Healthcare Clear Lake with gunshot wounds, where they're being treated. We don't know that person's condition.
Police say the third victim was involved in the shooting, but he is not cooperating with police at this time.
In a search of the immediate area, police say the couldn't locate a suspect who is said to have fled on foot.
The only description of the suspect is that they were wearing red clothing and eventually got into a black car or white truck after fleeing on foot, police say.
Anyone with information should contact the La Marque Police Department immediately at (409) 938-9269.