Authorities said 45-year-old Chau Thi Thu Nguyet was last seen at home in the area of Westminster and Newland streets around 1 p.m. on Tuesday.
They said she was believed to be seen walking from the Sprint Store located at the Orange Mall in the area of Tustin Street and Meats Avenue around 7 p.m. that same day.
She is 5 feet 2 inches tall, 100 pounds, with black hair, brown eyes, and is missing her front teeth. She is wearing the same sweater in the photograph above.
Police say she has the mental age of a 6-year-old, is non communicative and can seem very timid and afraid when approached by strangers.
Anyone with information is urged to call the Westminster Police Department at (714) 548-4600.