Three Mitsubishi group companies placed advertisements in a publication produced by a flight attendant school at the request of "sokaiya" extortionist Taichiro Otake, police sources said Friday.

Otake was arrested Wednesday, along with his wife, on charges of receiving payoffs from the firms in violation of the Commercial Code. About half of the ad fees paid by Mitsubishi Electric Corp., Mitsubishi Estate Co. and Mitsubishi Motors Corp., which also went to an aircraft magazine, are believed to have been channeled to Otake as payoffs so he would refrain from disrupting shareholders' meetings, the sources said.

The Metropolitan Police Department is treating the ad deals as new proof of the collusive relationship between Otake, 55, his wife, Masao, who runs the school, and the Mitsubishi group companies, they said. The MPD turned the couple over to prosecutors Friday in connection with payoffs they accepted from the companies. Such payoffs would be in violation of the Commercial Code, they said.

According to the MPD investigation, the three companies placed ads in the flight attendant publication and in the aircraft magazine, put out by a publishing house in Tokyo's Shinjuku Ward.

Annual fees for the advertisements amounted to about 2 million yen per publication and half of the fees paid to the publishing house were rerouted to Otake, the sources alleged.

Masao Otake's school has placed ads in the flight attendant magazine for about 10 years, and she offered to arrange the ads for the publishing house about eight years ago, the sources said.

Sources at the Mitsubishi firms were quoted as telling investigators they were aware that half the advertising fees went to the racketeer. It was also learned Friday that the school described itself as an institution designated by Japan Air System in pamphlets distributed to would-be students without obtaining the airline's consent.