(NEW YORK) -- At least one of the big questions surrounding last week's disastrous Carnival Triumph cruise excursion appears to have been answered.

Much of the power was lost aboard the vessel a week ago Sunday in the Gulf of the Mexico after an engine fire.  It took five days for the crippled ship to be towed to Mobile, Ala.

On Monday, the U.S. Coast Guard said a leak in a fuel return line sprayed diesel fuel onto a hot surface, thus causing the engine fire, which was quickly extinguished.

However, the damage was done as the crippled cruise ship with 4,200 passengers and crew members floated helplessly 150 miles from the Yucatan Peninsula, awaiting tug boats to rescue the Triumph.

In the meantime, the stranded passengers tweeted about backed-up toilets, short food supplies and even shorter tempers.

A complete Coast Guard investigation of the incident could take six months to complete.

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