Prosecutors plan to question a Democratic Party of Japan lawmaker who was once an aide to DPJ President Ichiro Ozawa in connection with the fundraising scandal that led to the arrest last week of Ozawa's chief secretary, sources said Tuesday.

The Tokyo District Public Prosecutor's Office is expected to seek an explanation from Lower House lawmaker Tomohiro Ishikawa, who is suspected of crafting funding reports for Ozawa's fundraising body, they said.

Prosecutors believe Ishikawa can help them learn how the fundraising body received allegedly illegal donations through dummy groups linked to general contractor Nishimatsu Construction Co.

Ishikawa, whose home district is in Hokkaido, became a secretary for Ozawa in 1996 and won a Diet seat for the first time in March 2007.

"It is impossible to have known that the donation was coming from Nishimatsu Construction," Ishikawa said

It is believed that the period Ishikawa was working for the fundraising body, called Rikuzankai, partly overlapped with that of Takanori Okubo, Ozawa's chief secretary arrested last week.

Okubo is suspected of taking ¥21 million in illegal donations from Nishimatsu from 2003 to 2006 and reporting them as coming from groups that turned out to be dummy organizations, a violation of the Political Funds Control Law.

In the political funding reports from 2000 to 2004 for Rikuzankai, Ishikawa's name appears as the person in charge of clerical work. Okubo has been in charge of accounting since 2000, and the two are believed to have worked together for several years.

The lawmaker said his job at the organization included creating political funding reports as well as soliciting fundraising party tickets.

The prosecutors are expected to confirm whether he was aware of the possible illegality of the Nishimatsu-related donations, the sources said.