Deputies responded to the house in the 3800 block of Charriton near Fern Meadow around midnight.
The people say they came home and found the man shot to death inside their living room.
The front door was damaged, but it's not clear if there was a break-in.
So far, no one knows who the dead man is or how long he was inside the home.
Investigators say that, based on the people they interviewed, he doesn't live in the area.
If you have any information, you're asked to contact the Harris County Sheriff's Office.