Cho Hyun-oh, who recently stepped down as chief of the National Police Agency, made allegations in 2010 that the late leader kept money in a bank account under a borrowed name, suggesting corruption.

Roh's bereaved family sued Cho for libel, punishable with fines and imprisonment.

"I regret (my comments)," Cho told reporters late Wednesday after questioning at the Seoul Central Prosecutors' Office, refusing to disclose what was discussed during the seven-hour questioning.

Roh jumped to his death in 2009 amid an investigation into claims his family received bribes. His death provoked criticism of politically-motivated investigations his supporters said were aimed at tarnishing Roh's image.