It happened just before midnight near a store on Weston Street and Kelso Street, near 610 South Loop.
Emergency crews found good Samaritans rendering aid to a man who was shot several times, but Houston Fire pronounced the man dead. Investigators believe he was an employee of the liquor store.
Police said the suspect also stole the victim's car before leaving the area.
"We have a couple witnesses that were driving by," HPD Lt. Wilkens said. "They believe they saw our suspect possibly shooting into a vehicle our complainant was sitting in...once the shooting occurred, they believe they saw our suspect dragging the complainant out of the vehicle."
Police said they're looking for a dark, smoke-colored Toyota sedan with at least one bullet hole in one of the windows.
Police only have a generic description of the suspect and ask anyone with more information or video to contact HPD's Homicide Division.