Prosecutors on Friday seized and searched the office of Woo Byung-woo, a former presidential official who allegedly played a crucial role between former President Park Geun-hye and her confidante Choi Soon-sil.

The process, however, took place following a voluntary submission format, as Cheong Wa Dae once again refused to let investigators onto its grounds, citing military confidentiality.

The special investigation headquarters under the Seoul Central District Prosecutors’ Office raided three of the offices affiliated to the senior presidential secretary for civil affairs, starting from 4:40 p.m. Friday, according to the Blue House and prosecution officials.

The raid, which was the third such attempt since the Choi scandal broke out late last year, was thwarted upon the resistance of the Blue House.

“Prosecution officials reached the Yeonpoong Gate (which is the main entrance gate to the Blue House), where they are discussing the detailed means of the search,” said spokesperson Jung Youn-kuk in a text message sent out to reporters.

The presidential office, which is temporarily steered by acting President and Prime Minister Hwang Kyo-ahn, retained its previous stance that no forceful entry may be allowed due to state security reasons.

The post of senior presidential secretary for civil affairs was previously occupied by Woo Byung-woo, who is currently under investigation over his suspected connivance or assistance in Choi’s meddling in state affairs.

Though his arrest warrant was earlier dismissed by the court, the former presidential legal affairs chief is still considered a central figure in the extensive corruption scandal which led to Park’s ouster upon her impeachment on March 10.

The allegations related to him, if proven, are expected to add momentum to the prosecutors’ ongoing investigation of Park, possibly encouraging them to file for her arrest warrant early next week.

“We are thoroughly reviewing all documents and evidence related to former President Park, but due to the complexity of the case, (the decision on the arrest warrant) is not likely to come within this weekend,” an official of the investigation team told reporters Friday afternoon.

The ousted president returned to her private house on Wednesday morning after an intense 21-hour inquiry on criminal charges in connection to Choi.

Investigators are expected to make an indictment early next week, upon which they will decide on whether to ask the court to issue a writ on Park.

By Bae Hyun-jung (tellme@heraldcorp.com)