A 72-year-old man traveling solo on a Princess Cruise ship has disappeared, and authorities believe he fell overboard. The incident came to light Monday morning when the Ruby Princess docked in San Francisco after a trip to Ensenada, Mexico, which began on November 27th. Crew members were unable to locate the man upon the ship's return.

An extensive search, involving reviews of CCTV footage and multiple sweeps of the vessel, proved unsuccessful. The cruise line spokesperson, in a statement to the New York Post, confirmed these efforts and indicated the incident is being treated as a man overboard situation.

U.S. Customs and Border Protection are now leading the investigation, with full cooperation from Princess Cruises. The U.S. Coast Guard also participated in the search, but their efforts were suspended late Monday afternoon. The exact circumstances surrounding the man's disappearance remain unknown.