The prosecution had requested for a court warrant to search both Yang’s residence and vehicle, but was issued a warrant for only Yang’s vehicle Sunday, as the court noted that not enough has been proven to raid his home.

The prosecution, nevertheless, searched his study, citing a clause in the warrant that says they can search the place where an item subject to confiscation is kept, if it is confirmed that the item is there.

Yang and his lawyer, who was present during the search, told investigators that the USB drive Yang took out of the Supreme Court upon his retirement was kept in his study, prosecutors said.

The investigation into judicial power abuse allegations during Yang’s time as chief justice from September 2011 to September 2017 began in June this year, and it is the first time the court has issued a warrant against him. The court rejected a search warrant request in July.

Prosecutors suspect the National Court Administration under Yang interfered with rulings on politically sensitive cases such as those concerning victims of forced labor under Japan’s colonial rule, a corrupt judge in Busan and stripping the Korea Teachers and Education Workers’ Union of its legal status.

The NCA had written memos analyzing the political and social impact of possible rulings on these cases, and shared them with the presidential office under former President Park Geun-hye.

Yang, appointed to Supreme Court chief justice by former President Lee Myung-bak, served most of his six-year term under Park, who took office in early 2013 and was impeached and removed from office last year.

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