Kim Paik-joon, who served as senior secretary for administrative affairs to Lee between 2008 and 2012, is suspected of receiving money from the National Intelligence Service on a regular basis. Prosecutors suspect that Kim and two other then presidential officials received a total of about 500 million won (US$472,022) from the NIS.

"I will be sincere" during the questioning, Kim told reporters after arriving at the Seoul Central District Prosecutors' Office. 

Kim is one of the closest aides to Lee and has often been dubbed his "butler."

Prosecutors were expected to question him about why he received NIS money, where he spent it and whether higher officials, including Lee, were involved. 

Prosecutors asked Kim to appear for questioning Friday, but Kim didn't comply with the summons. Prosecution officials asked Kim again to come to the prosecutors' office Saturday.

On Friday, prosecution investigators raided the residences of Kim and the two other secretaries -- Kim Hee-joong, one of Lee's private secretaries, and Kim Jin-mo, an ex-official at Cheong Wa Dae's civil affairs office. The two also underwent overnight questionings before leaving the prosecutors' office until early Saturday morning. (Yonhap)