A missing American sailor whose disappearance at sea on June 8 sparked a massive search of thousands of square kilometers of ocean by the U.S. Navy and Maritime Self-Defense Force has been found — hiding aboard his own ship.

The sailor, Peter Mims, was found in the engineering spaces of the guided-missile cruiser USS Shiloh on Thursday, U.S. Pacific Command spokesman Lt. Cmdr. Matt Knight told The Japan Times.

"The circumstances surrounding Petty Officer Mims' disappearance are under investigation," Knight said.

The discovery that Mims had been aboard the ship the entire time was first been reported by the Navy Times newspaper.

Mims, who enlisted in the Navy in February 2014, and reported to the Shiloh in August of that year, was reported missing and assumed overboard June 8 at about 9:30 p.m. while the ship was conducting routine operations 180 miles east of Okinawa.

His disappearance prompted a huge, 50-plus hour search effort by the U.S. Navy, MSDF and Japan Coast Guard in Japan's southern waters. The ocean search was suspended Sunday, but the crew of the Shiloh continued their search on board the vessel.

"We are thankful to have found our missing shipmate and appreciate all the hard work of our Sailors and Japanese partners in searching for him," Rear Adm. Charles Williams, commander, Carrier Strike Group 5 and Task Force 70, said in a statement. "I am relieved that this Sailor's family will not be joining the ranks of Gold Star Families that have sacrificed so much for our country."