HONOLULU (AP) — A Coast Guard rescue swimmer is spending time in the brig while the service investigates his three-month disappearance as it was preparing to discharge him for illegally using marijuana.

The Coast Guard on Wednesday launched a weeklong review of Petty Officer 1st Class Russell Matthews' case, spokesman Chief Warrant Officer Gene Maestas said.

Matthews is being held at a Navy-run facility in Pearl Harbor for detained personnel.

He hasn't been arrested. But his commanding officer, Capt. Timothy Gilbride, the commander of Coast Guard Air Station Barbers Point, ordered Matthews be confined because his unauthorized absence and the circumstances surrounding his disappearance make him a flight risk, Maestas said.

Matthews showed up at his home over the weekend, more than three months after his wife reported him missing and government agencies launched an extensive search for him both on land and at sea.

Honolulu police said Matthews returned home Sunday, but he was incoherent and taken to a hospital for observation. He later called his command.

Tripler Army Medical Center released Matthews on Tuesday night.

When the 36-year-old vanished in October, he was in the process of being discharged from the Coast Guard for illegal use of marijuana, Maestas said.

Maestas said he doesn't know where Matthews has been or what he's been doing since he went missing in October. He said that would come out in the investigation.

"We want to know, too," Maestas said. Continued...