Multiple stations were checked by officers and station agents in an attempt to locate a missing 80 year old male with dementia. After a system-wide page was made, a patron reported seeing the male on a train approaching West Oakland Station. The station agent located a man matching the missing person's description, but he shook his head "no" when asked if he was the missing person. Because the missing man spoke little English and suffered from dementia, an officer was also dispatched to look for the man. Resonding officers were unable to locate the man on the train being held. Trains were delayed approximately 18 minutes. A sergeant located the missing man at Concord Station at approximately 1420 hours.