Investigators believe the same person killed all three, and that the victims knew their killer.
The three men were all shot at around 10pm Sunday at the Gallery at Champions apartment complex off FM 1960 and Kuykendahl. Two of them died there, while the third was rushed to the hospital where he later died.
"I just heard some boom, boom, noise like boom, boom, boom," said neighbor Carlotta Briggs.
She says she opened her door to find 16-year-old Jeffrey Madrid lying on the ground, bleeding from gunshot wounds to his abdomen. He was one of the three men fatally shot at the complex.
"The ambulance came. They were trying to pick him up, and his intestines were falling, coming out, they tried to put it back in. It was just a gruesome scene," said Briggs.
Madrid was taken to the hospital where he was pronounced dead. His uncle and cousin have no idea why someone would target Madrid, who they say was a hard-working young man who had earned his GED so that he could work with his father as a landscaper.
"He was a laid back kid, never had any problems," said Hector Argueta, Madrid's uncle. "I never knew him to have any enemies."
"It was a terrible surprise for us," said Eddie Castellanas, Madrid's cousin.
Detectives found two other men who'd been shot to death inside a nearby upstairs unit. They say there was no evidence of a forced entry, and that the men had not been tied up -- factors that may indicate they knew their killer.
"None of the victims were bound or tied up, there was no forced entry into the apartment itself," said Sgt. Greg Pinkens with the Harris County Sheriff's Office. "There was evidence of several rounds being fired, but we don't know at this point who was doing the firing."
Witnesses say the gunman is a white or Asian male, and that he was driving a gold or dirty white 2005 Toyota Corolla.
Anyone with information is asked to call Crime Stoppers 713-222-TIPS.
