Dominic William O’Carroll, a 67-year-old Irish citizen, is still missing after a search by the United States Coast Guard was called off on Tuesday afternoon.

Mr. O’Carroll was found to be missing after a passenger count aboard the Horizon Croisières de France early Monday morning, according to a Coast Guard press release. The count had been initiated after a crewmember spotted an object going overboard, the release states.

At the time of the report, the ship was about 16 nautical miles south of Vieques, Puerto Rico, on its way from the Dominican Republic to St. Maarten. 

“The circumstances surrounding the disappearance of this passenger remain unclear,” said Captain Robert Warren, USCG Sector San Juan commander, after the search was called off Tuesday afternoon. “Our thoughts and prayers are with his family and loved ones during this most difficult time.”

During the search, Coast Guard rescue crews conducted 12 air and surface searches covering about 1,265 square nautical miles, an area approximately one third the size of Puerto Rico.

Mr. O’Carroll was last sighted by security cameras in several locations aboard the cruise ship prior to the incident, according to the release.

Coast Guard watchstanders near San Juan, Puerto Rico received notification of the incident from ship officials at about 5 a.m. Monday. A Coast Guard helicopter was launched and the Coast Guard Cutter Drummond was diverted to search for the missing passenger.