SAN FRANCISCO (KRON) -- Princess Cruises officials believe a 72-year-old man went overboard on Monday before the Ruby Princess cruise docked in San Francisco. "Princess Cruises is saddened to report that a 72-year-old American male is believed to have gone overboard earlier today ahead of the arrival of Ruby Princess into San Francisco," a statement said in part. Body found in Piner Creek in Santa Rosa identified U.S. Customs and Border Protection is reviewing the incident. Workers have searched the ship and reviewed surveillance footage. Princess Cruises' statement said it has "ruled out other possibilities" and is treating the matter as a man overboard. The man was traveling alone, according to the cruise company. There is no information available as to his condition. "We extend our heartfelt condolences to the family and friends of the guest who was traveling alone," the statement said. The ship arrived in San Francisco at 6:50 a.m. Monday after a five-day venture to Ensenada in Mexico. Later on Monday, it will leave for a 16-day trip to Hawaii.