A sergeant took a missing person report from a mother who reported her 41-year old son was overdue and missing. The missing son is autistic and lives at a group home in Fremont. The mother stated the son was dropped off at the Fremont station at 0900 and was to travel to the El Cerrito Del Norte station; which he has done in the past. As of 1215 hrs, the son had not arrived at the El Cerrito Del Norte station. The son’s description was broadcasted via police radio and a request made to BART Central to broadcast the same to train operators, and station agents. The group home where the son lives was also contacted. A missing person’s report (MUPS) was completed and the Criminal Investigations supervisor notified, as the missing son could be “at risk.” At 1234 hrs, the son was located safely at the Fremont station. Apparently the son got lost and returned to the Fremont station.