Heo Young Joong, a former real estate developer on trial in the Itoman case, has recently been questioned by prosecutors over 1 billion yen that he allegedly gave the former chairman of Wakachiku Construction Co. as funds for bribing lawmakers, investigation sources said Thursday.

Heo, known for his ties with the underworld, is believed to have introduced former Wakachiku Chairman Hiroshi Ishibashi to ex-Construction Minister Eiichi Nakao, who was arrested last month for allegedly receiving 30 million yen in bribes from Ishibashi in 1996 as reward for giving favors to Wakachiku over public works bidding.

The 30 million yen that went to Nakao is said to be part of the 1 billion yen that Heo handed to Ishibashi as funds earmarked to curry lawmakers' favor.

Ishibashi, who has not been arrested for bribery because of the statute of limitations, has told prosecutors that out of the 1 billion yen fund, he gave more than 100 million yen each to two other unidentified Lower House members of the Liberal Democratic Party, the sources said.

Ishibashi is also believed to have handed Nakao 40 million yen more, and investigators pressed Heo for further details on how the 1 billion yen was used, they added.

Heo reportedly approached Ishibashi to defraud the businessman in 1996. In the process, Heo allegedly gave the 1 billion yen to Ishibashi, telling him to use the money in accordance with his instructions to forge ties with political and business leaders.

Heo was served an additional warrant last March over the fraud case involving Ishibashi, and is being held at the Tokyo Detention House.

In the Itoman case, Heo is accused of causing financial damage to the now-defunct trading firm Itoman Corp.