Neither victim has been identified.
Harris County sheriff's deputies responded to the Park Village apartment complex, located at 14100 Rio Bonito Rd., around 4:51 p.m. One man was dead in the front seat of a Nissan sedan that had run into a curb in front of the leasing office.
The car's sunroof was shattered. The other victim was lying dead on the ground.
"It appears to be a robbery at this time. We have a suspect vehicle, a white sedan possibly occupied by three adult males, that fled the complex," explained Sergeant Eric Clegg with the HCSO Homicide Unit. "We do not have a suspect right now."
Officers do not believe the victims lived in the complex. Many residents describe it as peaceful but with a few recent robberies.
"I never witnessed anything like this on this magnitude and in broad daylight," said a woman who gave only her first name, Sybil.
"It's ridiculous. Never saw it before," Ronnie Mitchell said.
Anyone with information on the deadly shooting is asked to contact Crime Stoppers or the HCSO Homicide Unit at 713-274-9100.
Follow Jessica Willey on Facebook and Twitter.