A Los Angeles man allegedly confessed to killing his wife aboard a cruise ship on the night of his 55th birthday, court documents said.

Robert John McGill was charged with murder in the death of his wife Shirley, whose body was found Tuesday night in the bathroom of the couple's cabin aboard the Elation, a Carnival Cruise Lines ship sailing off San Diego.

McGill allegedly confessed to the killing after investigators noticed his knuckles "appeared as if he had been in a fight," a court affidavit said.

Shirley McGill died from strangulation and blunt-force injuries to the head and chest, the San Diego County medical examiner ruled Friday.

Robert McGill was ordered held without bail after prosecutors said he posed a flight risk and was a danger to the community, the San Diego Union-Tribune reported Saturday.