Presidential secretary Song In-bae returned home late Sunday after being questioned for over 13 hours as part of the probe into the online opinion rigging scandal involving the blogger "druking."

Song left the office of the independent counsel team in southern Seoul at around 11 p.m. Sunday. 

He told reporters that he provided a detailed and honest testimony, expressing hope that the investigation team will shed light on the scandal soon. 

However, Song refused to answer reporters' questions regarding major allegations against him.  

The presidential secretary is known to have introduced the blogger to South Gyeongsang Province Governor Kim Kyoung-soo in June 2016 when Kim was a ruling Democratic Party lawmaker.

Song reportedly claimed during the top office's internal probe that he met the blogger four times between June 2016 and February last year and received two million won from the blogger.

The special prosecutors reportedly grilled Song on allegations that he communicated with “druking” before the presidential election last year and was aware of the opinion manipulation by the blogger's group. 

Meanwhile, the prosecution plans to summon and question soon another presidential official, Baek Won-woo, on allegations that he met a lawyer in March, who was recommended to the top office by “druking” for a consular post.