A coastguard who vanished three months ago has returned home confused and unable to tell his wife where he had been.
Petty Officer First Class Russell Matthews disappeared in October leaving behind just an abandoned car.
Despite a 10,000-square mile of both land and sea along the coast of Hawaii, no traces of the 36-year-old could be found.
His car was discovered at Kaena Point, a remote area of Oahu.
The search for Mr Matthews, who has been a coast guard for 15 years, was eventually called off on December 13.
However, Mr Matthews, a rescue swimmer, suddenly reappeared at his home on Sunday but was incoherent and had to be taken to hospital for treatment, according to the Honolulu Police Department and Coast Guard.
Lt Gene Maestas, the Coast Guard spokesman, said the service did not know where Mr Matthews had been or what he had been doing since his wife reported him missing on October 9.
He said: "This is not the norm for the Coast Guard. In my 28-year career in the Coast Guard, I have never come across a case like this."
Coast Guard investigators were sent to see him to confirm his identity after he called his employers from a Honolulu medical centre.
Lt Maestas said that Mr Matthews would not be questioned until he was released by doctors but that the service would be investigating his disappearance.
He said: "We'll try to find out why he disappeared and all the details surrounding his case."
Sgt Kim Buffett, of Honolulu Police, said detectives had no reason to pursue the case as it is not against the law to be missing, she said.
She said the police case was closed now that Mr Matthews has been found.