Mentally challenged persons such as autistic children and Alzheimer's patients can become lost and they are hard to find because they have difficulty communicating or they are confused and disoriented. The present invention provides an apparatus, system and methods for locating lost persons (or animals or packages) whether they are indoors or outdoors. The apparatus comprises a cellular telephone unit which can be activated by a RF signal and which a child or patient can wear. The wearable unit can be activated by a caregiver's smart phone having a locating application installed therein. The locating application enables the caregiver to locate the lost person using radio direction finder triangulation when the lost person is within a few hundred feet of the caregiver. When the lost person is further away, the locating application employs cell phone tower triangulation or the wearable unit GPS/Assisted GPS application to determine an approximate location of the lost person. As the caregiver moves close enough to the approximate location, the radio direction finder triangulation is used to calculate a more exact location to find the lost person.