South Korean special investigators raided the offices of "shadowy doctors" for President Park Geun-hye Wednesday over allegations they provided undue medical treatment to her.

The independent counsel team looking into the corruption scandal that has led to her impeachment said its investigators visited some 10 places, including plastic surgeon Kim Young-jae's clinic and home in Seoul.

He is suspected of treating Park with the help of her friend Choi Soon-sil without going through due security procedures.

Lee Kyu-chul, spokesman for the probe team, said they are also investigating allegations that Kim illegally prescribed the psychotropic drug propofol.

The seizure and search indicated that the investigators are digging into Park's alleged inaction during a ferry disaster in 2014.

Her office has yet to clarify what she was doing exactly during the first seven hours of the Sewol sinking, which killed more than

300 people, failing to quell rumors that she might have received cosmetic treatment during the critical hours. 

Investigators have been looking into allegations that doctors violated medical law by giving prescriptions or treatment to Park without leaving official records. There have been suspicions that the doctors were given business favors in return.

Seoul National University Hospital, headed by Suh Chang-suk, was also known to have been searched by investigators. Suh served as Park's official doctor from 2014 to earlier this year. Lee said they are investigating whether Suh neglected his duty by overlooking such irregularities while being aware of them.

Meanwhile, the investigation team has asked the Financial Supervisory Service to provide property details for some 40 people related to Choi, who is at the center of the scandal. Choi is currently standing trial over a string of corruption allegations. (Yonhap)