INDIANAPOLIS | A passenger died in the restroom during an American Airlines flight and wasn't found until the cleaning crew boarded the plane after it landed, a federal lawsuit contends.

Taisuke Matsuo apparently had a fatal heart attack after he went to the restroom during a flight from Tokyo to Chicago during the first leg of a trip home to Indianapolis, according to the suit filed by his wife, Carolyn D. Watts. The suit was filed Monday in U.S. District Court in Indianapolis.

After the plane landed at Chicago O'Hare International Airport on April 13, 2005, passengers and flight crew disembarked and the jet was taken to another gate for cleaning, according to the complaint. Workers cleaning the plane then discovered the bathroom was locked from the inside and found the 66-year-old Matsuo's body about two hours after the jet landed.

Tim Smith, a spokesman for American Airlines in Fort Worth, Texas, said the company does not generally comment on pending litigation.

The lawsuit accuses American Airlines of negligence and seeks damages of about 100,000 Special Drawing Rights, an international unit of account. The damages would amount to some $150,000 in U.S. dollars at Wednesday's rate of exchange.