A parliamentary inquiry into the scandal surrounding President Park Geun-hye and her close friend Choi Soon-sil produced a rare new testimony Thursday that the presidential office conducted a massive surveillance operation on the nation’s top justice.

Cho Han-gyu, a former publisher of local daily Segye Ilbo, claimed to have documents that reveal the presidential office spied on senior members of the judiciary branch, including the Supreme Court’s Chief Justice Yang Sung-tae.

“It is a grave violation of our Constitution and the democratic principle of separation of powers,” said Cho.“(The surveillance) was not about finding out significant wrongdoings. Everyday life was surveilled and reported to the presidential office.”

The two-page document, whose copied version was only submitted to the lawmakers, contained information about how Yang had reacted to a report about him hiking with his colleagues during working hours.

Rep. Park Bum-kye of the main opposition Democratic Party of Korea said that the document was created by the National Intelligence Agency, the top spy agency which had been accused of surveilling civilians during the previous conservative Lee Myung-bak government.

Cho was among the witnesses who testified about the allegations surrounding Jeong Yoon-hoe, the ex-husband of Choi. Cho’s newspaper was the first to expose that President Park had secret advisors -- Jeong and Choi -- who wielded undue influence over the president.

He also revealed that Jeong took 700 million won ($593,000) in return for giving a government post to an individual, who held a position amounting to vice prime minister when Jeong worked for President Park. Cho said the individual still works for the government, but refused to reveal the identity.

Before the report in late October that Choi was found to have manipulated government affairs, Jeong was considered to be Park’s most close confidant. Chung had served as a parliamentary aide to Park when she was a lawmaker in 2002.

When asked by the lawmakers whether Choi became closer to the president after her divorce with Jeong, Cho replied, “Yes.” The publisher also claimed that Cheong Wa Dae arranged the divorce between Jeong and Choi in 2014.

But his series of revelations was overshadowed by the absence of Chung and other key witnesses connected to the scandal.

Among them was Park Gwan-chun, a police superintendent who worked at Cheong Wa De and who famously said, “In terms of the rank of power in the current administration, Choi comes first and Jeong second, followed by the president herself.”

The lawmakers also spent their time investigating the allegations that Ewha Womans University offered preferential treatment to Chung Yoo-ra, the daughter of Choi. Chung has been accused of receiving special favors in the admission process and her academic records at the nation’s longest-running women’s university.

But the university’s President Choi Kyung-hee denied any wrongdoing.

“We have underwent thorough investigation by the Education Ministry, but found out that we have never offered special favors to her,” Choi Kyung-hee told the lawmakers.

The controversy over Chung’s illicit admission to the school has prompted mounting calls for Choi Kyung-hee’s resignation. The students denounced the president for giving good grades to Jeong despite her long absences from the school and submissions of assignments past deadlines.

By Yeo Jun-suk (jasonyeo@heraldcorp.com)