Harris County sheriff's deputies say the mother hadn't heard from her 20-year-old son, Keshauwn Badger, in a few days and went to check on him Sunday night.
She went inside the house on Red Castle and Granite Park and found her son shot to death in the primary bedroom, deputies say.
Badger's van was also missing from the garage.
Deputies believe he may have been dead for several days.
"We're checking surveillance video in the neighborhood and the victim's house, trying to determine when the shooting occurred," Sgt. Ben Beall said. "We did find several shell casings in the house."
Deputies say there were no signs of forced entry.
There is no suspect description at this time. The case is being investigated by the Harris County Sheriff's Office Homicide Unit.
The missing van is described as a gray Dodge Caravan with paper plates from a recent purchase at an auction.