Denise disappeared from the Lancaster, California apartment she shared with her son, Daniel Spangle, on March 2, 1989. They were last seen by her boyfriend, when he left their apartment go to work. Two hours later, Denise's sister discovered them missing when she went to the residence. Authorities went to the apartment to investigate and found the front door open. The sliding glass door inside the residence was open a few inches as well, though it was a cold day. Police believe the door may have been forced open. A single muddy footprint was found on top of the air conditioning unit next to the sliding door, and the closet door in Daniel's bedroom was off its track. They both remain missing.