Local police on Friday raided a pension in Gangneung, on a tip-off from opposition party officials, and arrested some 30 people for making covert telephone calls to persuade voters to cast ballots for Ohm.

As the pension has not been registered as a campaign office, officials said such acts are in violation of the election law.

Investigators are studying email and phone records to find out whether Ohm knew or was involved in the calls. His camp has so far firmly denied the charges.

The main opposition Democratic Party rebuked Ohm’s denial, and added its voice to the accusations of his violating the election law.

“The GNP places the blame on the volunteers, but it is hard to believe that they could have organized such a costly project on their own, without the party or the candidate knowing,” said the DP spokesperson on Sunday.

Investigators are also seeking to find the source of the operation’s funding, including the money used to rent the pension.

Ohm, however, demanded that Choi and the DP wait for results from the police investigation, urging the him to refrain from rash slander.

The GNP candidate also countered by pointing to similar charges against the DP.

“The DP is also suspected of intentionally sending out fabricated SMS messages to some 220,000 citizens, a charge which has not yet been fully cleared,” Ohm said.

“We should all be patient until the police come up with an official result, in order to prevent these by-elections from becoming a set of mudslinging games.”

Choi claimed that the illicit call center scandal was a thoroughly planned election crime, whereas the SMS messages were sent due to a data processing error.

In his other campaign speeches, the DP candidate also demanded that Ohm end his candidacy in order to take responsibility for his alleged involvement in the alleged illicit campaign.

Both Ohm and Choi face another television forum late on Monday, the last before the Wednesday by-elections.

By Bae Hyun-jung (tellme@heraldcorp.com)