the person who offered the information," Hatoyama told DPJ lawmakers during a meeting in Tokyo.
Nagata read out the bogus e-mail in the Diet last month, claiming it was internal instructions by Horie to staff to transfer 30 million yen to the son of Liberal Democratic Party Secretary General Tsutomu Takebe to buy LDP election support in his campaign for the Sept. 11 general election. With Takebe's strong backing, Horie ran as an independent against an opponent to Prime Minister Junichiro Koizumi's postal reform efforts in the Hiroshima No. 6 district and lost.
The DPJ has had to publicly apologize and the incident has deeply damaged the image of the largest opposition party.
The freelance journalist, who has yet to be identified, allegedly gave the bogus e-mail to DPJ Nagata, who brought it up during a Feb. 16 Lower House Budget Committee meeting.
Katsuei Hirasawa, an LDP lawmaker who has been looking into the case, said he suspects Nagata paid the journalist for the information.
Hatoyama denied the allegation.
"That is not a fact. We have to reconfirm it (by contacting Nagata) again, but we have to consider some measures against (Hirasawa), too," he said, without elaborating.
The LDP formally accepted a letter of apology Friday from the DPJ, ending a battle over the credibility of what is now considered fake e-mail.
The LDP had sent a question via an open letter to the DPJ, demanding that the party clearly admit the e-mail was fake and there was no grounds for alleging that Takebe's son received shady money from Horie.
Some LDP lawmakers are still demanding that Nagata be stripped of his Lower House seat by a disciplinary committee, but they appeared to be a minority among the ruling bloc, Diet sources said.