Guzman-Mendoza was last seen in Tucson, Arizona on September 20, 2010. She left her job at the Mountain Oyster Club, a private dining club, in the vicinity of Speedway and Wilmot, at 8:30 a.m., just half an hour into her shift. She said she was felt sick and was going home. She normally took two buses to get between work and her home in the area of Ruthraff and Interstate 10.

Guzman-Mendoza never arrived home and has never been heard from again. Authorities determined she did board the first bus, and that morning her cellular phone pinged off a tower at Curtis and Kain, about a quarter of a mile from home. This was the last sign of her.

According to her family, Guzman-Mendoza is a devoted mother and a hard worker who would not have walked out of her life. She isn't married, wasn't dating anyone at the time of her disappearance and has no history of mental illness. She was also looking forward to the birth of her first grandchild. Because of her state of health and the circumstances of her disappearance, her loved ones fear for her safety. Since her disappearance, Guzman-Mendoza hasn't accessed her bank account or refilled her prescriptions. Her case remains unsolved.