The rival parties failed to finalize the format of their special investigation into the National Intelligence Service’s alleged political interference Wednesday due to differences over the member composition.

Representatives of the ruling Saenuri Party and the main opposition Democratic Party on the special committee met and discussed the detailed plans for the investigation, but butted heads over the former’s demand for the exclusion of some DP members.

“If the DP does not leave out the two lawmakers in question, the probe cannot progress at all,” said Saenuri Party Rep. Kweon Seong-dong.

DP Rep. Jung Cheong-rae, on the other hand, said, “It is difficult to accept the unreasonable and undue demand by the Saenuri Party at this moment.”

The two parties had agreed last week to launch a 45-day parliamentary investigation into allegations that the nation’s spy agency meddled in the presidential election last year by mobilizing an online smear campaign. The probe is also to look into whether the DP mistreated and violated the human rights of an NIS employee accused of posting political comments.

On Tuesday, Saenuri Reps. Chung Moon-hun and Lee Cheol-woo left the team demanding that two other DP members ― Reps. Kim Hyun and Jin Sun-mee ― leave as well as they were directly involved in the alleged harassment of the NIS member.

The probe is scheduled to be held until Aug. 15. Other preparations, including the list of about 113 witnesses and the procedure of questioning, were underway.

The Saenuri Party reportedly is pushing to include on the list former DP lawmaker Kim Boo-kyum, who is suspected of trying to bribe an NIS official last year for information, and the NIS worker who was allegedly harassed by the DP members.

The DP, in turn, is threatening to include former President Lee Myung-bak to question the previous government’s alleged involvement with the NIS’ campaign.

By Lee Joo-hee (jhl@heraldcorp.com)