First Lady Kim Keon Hee apologized for causing public concerns as she attended questioning by the prosecution, her lawyer said Thursday.

Kim's legal representative, lawyer Choi Ji-woo, said in a YouTube interview that she told the prosecution before the interrogation began on Saturday, adding that she feels sorry for letting the people down as first lady.

Amid growing criticism over speculations that the first lady was receiving preferential treatment by being questioned at a venue outside the prosecution's office, the lawyer stated it was for her safety and that he felt the criticism was unfair.

On Monday, Prosecutor General Lee One-seok apologized to the public, saying that holding such an interrogation outside the prosecutor's office undermined the rule of law and that he wasn't briefed about the case until it was nearly over.

Meanwhile, the Supreme Prosecutors' Office, the top office of the prosecution, announced Thursday that it would launch an internal probe into the Seoul Central District Prosecutors' Office. The investigation aims to determine if there were any discrepancies during the questioning of the first lady regarding her alleged acceptance of a Dior bag. The Seoul district prosecutors questioned Kim for about 12 hours on Saturday. According to local reports, the questioning was reported to the district office's command, including head Lee Chang-soo, at 8 p.m., and then to Prosecutor General Lee One-seok three hours later. This raised speculation about why he was not immediately briefed about questioning such a high-profile person and that the case was taking place somewhere outside of the office.