The Corruption Investigation Office for High-ranking Officials(CIO) says it will be difficult, for the time being, to summon South Korea’s Ambassador to Australia Lee Jong-sup for questioning. 

The CIO, which investigates crimes committed by senior officials, unveiled such a stance to reporters on Friday as it is looking into suspicions that Lee interfered in the defense ministry's probe into the death of Marine Corporal Chae Su-geun, who was swept away by a torrent during a search and rescue operation for flood victims last summer.

The agency cited that digital forensics and data analysis of seized materials have yet to be concluded and that it has yet to sufficiently conduct probes on witnesses. 

The CIO said it plans to inform Lee of a date for questioning after carefully reviewing and assessing progress in its investigations and after engaging in consultations with legal counsels. 

Upon arriving in the nation on Thursday to attend a government meeting, Lee had told reporters that he hopes to have the opportunity to undergo questioning during his stay after smoothly coordinating his schedule with the CIO.