Muhleman was living with her boyfriend in Fremont, California at the time of her disappearance. He is the father of their daughter and the couple reportedly had a stormy relationship.

Muhleman's boyfriend's sister was the last one to see Muhleman, at 9:30 a.m. on February 27, 1989 in Muhleman's home. Her boyfriend stated that he saw her at 8:00 a.m. that day before he left for work, and when he returned, she was gone. Muhleman's mother reported her missing two weeks later.

Although it was raining the day Muhleman disappeared, her coat was left behind. She was unemployed at the time of her disappearance and had a warrant out for her arrest for drug charges, but authorities do not believe she left because of the warrant. She kept in almost daily touch with her relatives prior to her disappearance, but none of them have heard from her since 1989.

Investigators initially suspected Muhleman's boyfriend in her case, but no evidence has been uncovered linking him to her disappearance. Foul play is suspected.