Prosecutors’ investigation into the alleged abuse of judicial power by the Supreme Court under former President Park Geun-hye has hit a snag, as the email accounts of retired judges involved were found to have been deleted.

Documents leaked from hard disks of staff members at the top court’s governing body under former Chief Justice Yang Sung-tae showed the National Court Administration had offered insights on the impact of possible future verdicts on politically sensitive trials to Park’s office, allegedly to curry favor with her.

Prosecutors are looking into whether Yang attempted to manipulate verdicts to win the former president’s approval for the establishment of a court of appeals.

Prosecutors have obtained evidence, for instance, suggesting Yang tried to defer a ruling on litigation involving Koreans forced into labor during Japan’s colonial occupation, as Park’s office sought to improve relations with Tokyo.

On Tuesday, prosecutors interrogated Park’s former chief of staff Kim Ki-choon, who was allegedly aware of such attempts by Yang and was briefed on them by lower Cheong Wa Dae officials who met with Lim Jong-hun, who was then deputy chief of the top court’s governing body.

Lim is suspected of ordering his staff at the National Court Administration to do background checks on judges critical of the Park administration and report on their activities.

He also ordered them to produce documents predicting the impact of possible verdicts on a slew of politically sensitive cases, such as the layoffs of temporary workers of the KTX high-speed rail company in 2008. The Supreme Court in 2015 overturned lower court rulings on the case, and allegations have been raised that Yang exerted his influence on the decision.

In late July, investigators at the Seoul Central District Prosecutors’ Office received court warrants to search the emails of Lim and two other retired judges, surnamed Shim and Lee, involved in the power abuse case, and requested the Supreme Court provide the materials.

The official email accounts of Shim and Lim had been deleted, however, as they retired in January and March last year, respectively. Lee’s email account has not been deleted yet, allowing prosecutors to obtain information from his account.

Suspicions the NCA had sought to politically bargain with Park’s office were raised as the prosecution looked into allegations the NCA blacklisted judges critical of Park, and inspected them.

Supreme Court Chief Justice Kim Myeong-soo, who was nominated by President Moon Jae-in in August last year, created a team to reinvestigate the suspected blacklisting of judges after an earlier internal probe under Yang concluded that although the NCA monitored judges’ research activities and tendencies in decision-making, there was no evidence that they suffered any disadvantages as a result.

The continued probe into the NCA’s monitoring of judges’ political orientations has led to controversy within the judiciary over related issues, such as whether the prosecution should be allowed to open by force hundreds of encrypted NCA files to possibly dig up more suspicions.

Judges have exchanged criticisms and blunt words via their internal online message board, prompting some to express concerns the continued probe is fueling conflicts among judges and distrust in the courts.

“It is a shame to see the judges, who should be independent, being divided like politicians as the investigations continue,” one judge told The Korea Herald.

“We are just waiting for this whole period of internal conflict stemming from the probe to pass.”

By Kim So-hyun (sophie@heraldcorp.com)