LOS ANGELES (AP) — Finding the cause of a major oil spill off Southern California, who is to blame and if they will be held accountable could take a long time.

The Coast Guard said Friday that investigators are trying to find a boat that is believed to have snagged the pipeline with its anchor in the past year.

The search for that vessel is among many avenues investigators are following from several federal and state agencies as they seek the source of the pipe rupture, how pipeline operators reacted to it and look into whether criminal charges are warranted.