A court late on July 15 rejected an arrest warrant for Lee Si-won, a former presidential secretary for public discipline accused of leaking investigative secrets in the death of Marine Corporal Chae, the Kyunghyang Shinmun reported.

Lee has been under investigation on suspicion of passing confidential details of the probe into the corporal's death to outside parties.

The court reportedly found the justification for detention insufficient, citing the defendant's right to mount a defense.

The denial complicates the special counsel's timetable. Prosecutors are expected to shore up the case before deciding whether to seek a new warrant.

The question of political interference in the Chae investigation remains one of the defining legal battles of the current government, and how suspects are detained will set the pace of the inquiry.