A Coast Guard official says the cause of the engine-room fire on the Carnival cruise ship Triumph was a leak in a fuel engine return line.
In a teleconference on Monday (local time), Commander Theresa Hatfield estimated the investigation of the disabled ship would take six months.
She said the Bahamas was leading the investigation, with the Coast Guard and National Transportation Safety Board leading US interests in the probe.
She said investigators have been with the ship since it arrived on Thursday in Mobile, and interviews have been conducted with passengers and crew.
The ship left Galveston, Texas, on February 17 for a four-day trip to Mexico. The fire paralysed the ship early on Sunday, leaving it adrift in the Gulf of Mexico until tugboats towed it to Mobile.