Theresa and her roommate, Christine Rusch (MP #35156), vanished from their apartment. They had both called in sick on the 25th.
Christine and Theresa are suspected victims of serial killer of Richard Grissom Jr. He was a maintenance man at the apartment complex where they lived, and had keys to all the units. He was tried and convicted of their murders but their remains have never been recovered. (Information retrieved from NamUs.gov)