An investigation into intelligence agents’ alleged interference in politics took a new turn over the weekend upon whistle-blowing by a police chief investigator that sent ripples through political circles and the nation’s intelligence agency.

Kwon Eun-hee, a former chief investigator at the Suseo Police Station, confessed Saturday through several media interviews that there was pressure from high-ranking police officers from the National Police Agency during the investigation against agents of the National Intelligence Service.

On Friday, Kwon, whose name was withheld at the time, claimed that the Seoul Metropolitan Police Agency constantly attempted to intervene in the probe into alleged online smear campaigns by NIS agents against opposition politicians in the December presidential election last year.

The exposure immediately stoked vehement protests from the opposition Democratic United Party, which condemned the authorities and demanded a thorough probe into former NIS chief Won Sei-hoon, former SMPA chief Kim Yong-pan and other high-ranking officials for their possible involvement.

“It is only right for the NIS chief to clarify an official position about this grave case where the agency manipulated public opinion under structural and systematic command to mislead the public by interfering in domestic politics,” DUP spokeswoman Rep. Kim Hyun said Sunday.

Kwon, who is now serving at the Songpa Police Station, said her team found it “difficult to focus on investigating the case from the beginning in last December through early February due to interference from the top echelons.”

Her team had requested an analysis of 78 keywords allegedly used by intelligence agents in their online campaigns to the SMPA but the Seoul police agency directed Kwon’s team to reduce the keywords to four, stressing the need for the probe to proceed quickly.

Kwon said she withdrew her team members dispatched to the SMPA for the case in protest over the direction.

The SMPA announced the interim results of the probe a few days before the presidential election, saying there was no evidence of illegal political interference by the nation’s intelligence agency.

Lee Kwang-seok, former chief of the Suseo Police Station, denied that the reduced number of the keywords was due to pressure from above, saying the investigation was thoroughly performed according to the rules.

Kwon was transferred to the Songpa Police Station in February before the investigation into the intelligence agents ended.

Critics and opposition politicians had been suggesting the behind-the-scenes influences on the investigation.

Pyo Chang-won, a former professor of police administration, urged police to not forget precedents in which overly loyal police officers “ended up in jail after deceiving the public” on his Twitter.

Others also voiced concerns over the damage the latest case would have on the integrity of police.

“If interference in the investigation (of the NIS agents) is confirmed, the credibility of the police investigation will be seriously damaged,” Hwang Jeong-in, chief investigator at the Gangnam Police Station, said on his Facebook account.

“The only way to root out interference from above is revealing unfair interference, and those who attempt to intervene in investigations should be brought to ruin.”

Last Thursday, the Suseo Police Station confirmed the agents’ intervention in politics, which would violate the NIS Act, but did not determine whether it was a violation of the Public Official Election Act banning public officials from participating in election campaigns.

Police officers handed over custody of the two NIS employees and a civilian to the prosecution for further investigation. A special investigative team of the Seoul Central District Prosecutors’ has begun reviewing investigative records and relevant evidence.

By Kim Young-won (wone0102@heraldcorp.com)