Prosecutors have questioned former Finance Minister Hiroshi Mitsuzuka in connection with wrongdoing involving indicted Diet member Yojiro Nakajima, sources said Wednesday.

Prosecutors believe money Mitsuzuka provided Nakajima, who resigned his Lower House seat Tuesday, was included in 20 million yen that Nakajima allegedly used to buy votes during the 1996 general election, the sources said.

Mitsuzuka, 71, former leader of a Liberal Democratic Party faction, provided Nakajima 5 million yen prior to the election to help him campaign in the poll, the sources alleged. Obtaining monetary assistance from faction leaders before an election has been routine for LDP lawmakers.

Mitsuzuka, who headed the faction now led by LDP Secretary General Yoshiro Mori, was not immediately available for comment. Nakajima, 39, pleaded guilty last week to providing 20 million yen to supporters to buy votes during the election.

He admitted to the Tokyo District Court that he gave some 20 million yen to three leaders of his support group.

Prosecutors also suspect Mitsuzuka introduced Nakajima to a man who later allegedly conspired with the arrested lawmaker to pose as a policy secretary to swindle tax money. Policy secretaries of Diet members are paid from the national coffers.

Nakajima formally submitted his resignation to the Lower House speaker through his lawyer Tuesday. He has been charged with taking bribes from Fuji Heavy Industries Ltd., buying votes in the 1996 general election in violation of the Public Office Election Law and submitting false statements on the use of political subsidies.

Nakajima was first arrested in late October on suspicion of submitting false statements on the use of political subsidies given to an LDP chapter.