Arson is now being suspected as the cause of the July 12, 2020 fire that ripped through the amphibious assault ship Bonhomme Richard, causing severe damage, and a sailor is being questioned as a possible suspect, according to Navy Times.

The fire lasted four days, and may be the worst non-combat vessel fire in US Naval history. The possible suspect was not detained. The incident is being investigated by both the Navy and Bureau of Alcohol, Tobacco, and Firearms (ATF).

The Bonhomme Richard was docked in San Diego undergoing $250 million in repairs and updates, and the process was nearly complete. It is unclear at this time if the ship can be saved, and it would cost $4 billion to replace it.