The jilted ex-boyfriend knew exactly how to get into the house.
The home, in the northwest Houston suburbs, is accessed by a key code.
After a couple of years since living there with a then-girlfriend, the man gave the combination a try today after banging on the garage door.
It worked, and at about 3.15am local time he slipped into the home, where authorities say he found his former girlfriend's new boyfriend and fatally shot him, then wounded her.
He then killed himself.