This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

SAN DIEGO (AP) — Arson is suspected as the cause of a July 12 fire in San Diego that left extensive damage to the USS Bonhomme Richard and a U.S. Navy sailor is being questioned as a potential suspect, a senior defense official said Wednesday.

The official, with knowledge of the investigation, spoke to The Associated Press on condition of anonymity to provide details not yet made public.

The amphibious assault ship burned for more than four days and was the Navy’s worst U.S. warship fire outside of combat in recent memory.

The future of the ship remains uncertain.

The amphibious assault ships are among the few in the U.S. fleet that can act as a mini aircraft carrier. If the Bonhomme Richard is not repaired, it could cost the Navy up to $4 billion to replace it, according to defense analysts.

The Bonhomme Richard was nearing the end of a two-year upgrade estimated to cost $250 million.