The Navy thought this sailor was lost at sea. He was just found alive - on his own ship.

After the Navy suspended the massive ocean search for her brother, who was thought to be lost at sea, Amy James said she still believed Petty Officer 3rd Class Peter Mims was still alive.

"I just can't believe he's gone," James told CBS affiliate WJAX. "Is this real? Is this a nightmare?"

She added: "He's still alive, he's got to be fighting for his life."

The USS Shiloh had reported Mims missing and presumed overboard just days earlier, on June 8.

U.S. Navy and Japanese Coast Guard ships and aircraft spent more than 50 hours covering about 5,500 square miles of the Philippine Sea looking for Mims before the search was suspended at midnight on June 11.

"The decision to suspend the search was not arrived at lightly," Rear Adm. Charles Williams said in a news release at the time. "Our thoughts are with our lost shipmate, his family, and the officers and crew of USS Shiloh."

The sailor's sister was hoping for good news, but said she was mostly just waiting for answers.

"Me and my family just want some peace," James told WJAX.

On Thursday, the Navy announced it had found Mims – alive and aboard the ship.

The Navy's 7th Fleet said Mims was found after the crew of the guided-missile cruiser continued to look for him on the ship. He has been transferred to the USS Ronald Reagan for a medical evaluation, and his disappearance is under investigation, according to a news release.

"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," Williams 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."

The 7th Fleet's news release does not say how Mims was found, or where on the ship he was located, and spokesman Navy Cmdr. Bill Speaks said he did not currently have details. The Navy Times reported that the missing gas turbine systems technician had been hiding in one of the engine rooms.

What happens next with Mims will be driven by the investigation's findings, Speaks said.

Mims, from Interlachen, Fla., enlisted in February 2014 and reported to the Shiloh in August of that year, according to the Navy.

He disappeared last week while the ship "was conducting routine operations 180 miles east of Okinawa, Japan," the Navy said.

The search for Mims involved more than half a dozen U.S. and Japanese vessels along with helicopters and fixed-wing aircraft from multiple American ships.

When the Navy suspended its search, Williams, the rear admiral, said the decision "was not arrived at lightly," adding: "Our thoughts are with our lost shipmate, his family, and the officers and crew of USS Shiloh."

Just as the search for Mims was ramping up, the U.S. Navy called off an unsuccessful search for a sailor aboard the USS Normandy who was seen going overboard during a training exercise off the coast of North Carolina.