Former vice defense minister Shin Beom-chul has left the ruling People Power Party(PPP), with some speculating his decision was influenced by the investigation over his alleged role in interfering with a military report on a probe into the death of Marine Corporal Chae Su-geun last year.

Shin, who lost as a PPP candidate in the recent general elections for the Cheonan A district of South Chungcheong Province, told KBS that he intends to retire from politics after suffering two defeats in the same constituency.

Some within political circles suspect that Shin is leaving the party to avoid causing any further burden ahead of the Corruption Investigation Office for High-ranking Officials'(CIO) expected summons of the former vice minister for questioning.

Shin is suspected of involvement in the defense ministry's alleged order to hold off on sending a report from an initial Marine investigation to the police.

Attending a parliamentary committee plenary meeting as vice defense minister last August, Shin had said that it was his understanding that President Yoon Suk Yeol and then-defense minister Lee Jong-sup had not discussed the matter over the phone.