Disputes intensified on Monday over the spy agency’s alleged role in illegally collecting personal information of a boy suspected to be the illegitimate son of former prosecution chief Chae Dong-wook.

The prosecution investigating the case said it has secured testimony from an education officer that he was requested by a National Intelligence Service agent to check the name of the boy’s father.

It is the first time that the NIS is speculated to be involved in the illegal access of personal information of the child.

Local reports quoting investigators said that the education officer made a phone call to the principal of the school the boy attended at the time. But the administrator declined to answer, citing legal issues, according to reports. The prosecution plans to summon the NIS agent soon to check on facts, they added.

Late last year, a Cheong Wa Dae official was found to have attempted to open the family registration file with help from a local ward official. The Blue House described the official’s behavior as a “personal aberration.”

But the involvement of the Cheong Wa Dae official fueled suspicion that the Presidential Office might have played a behind-the-scenes role in taking out Chae.

The main opposition Democratic Party alleges that Cheong Wa Dae may have attempted to expel Chae by investigating his personal affairs. Chae, the first prosecutor general appointed by President Park Geun-hye, spearheaded the prosecution’s investigation into the NIS’ alleged political interference in last year’s presidential election. The spy agency has been suspected of ordering its agents to post online comments degrading Moon Jae-in, then the presidential candidate from the DP.

The prosecution, under Chae’s direction at the time, seemed to be making progress in the election-meddling case. But Chae resigned in September, soon after a Korean conservative daily raised allegations that he had fathered a son out of wedlock. The ex-top prosecutor denied the allegations and said he was resigning from the post because such reports would make it difficult for him to carry out his duties.

The DP claimed that the spy agency had begun to collect personal information on Chae in June by the time its former chief Won Sei-hoon was arrested by the prosecution.

“What appears obvious is that an operation of vengeance had been carried out to force former Prosecutor General Chae Dong-wook out,” Rep. Shin Kyoung-min, a member of the DP’s Supreme Council said in a meeting on Monday.

The NIS, in a rare response, denied its alleged involvement and said it was highly personal.

“In an internal investigation, the intelligent officer S contacted the education officer to check on facts after he heard rumors of Chae’s extramarital child,” an NIS official said.

“(The NIS agent) had nothing but the response that the principal had declined to answer,” an NIS official said.

By Cho Chung-un (christory@heraldcorp.com)