The state anti-corruption investigation agency summoned again the defense ministry's general counsel, a key suspect in its investigation into alleged state intervention in the case of a Marine's death during a search and rescue operation in heavy rain last year.

The Corruption Investigation Office for High-ranking Officials(CIO) is questioning Yoo Jae-eun, the defense ministry's chief legal officer, on Monday morning, on charges of abuse of power and obstruction of the exercise of one's rights.

Yoo, who was summoned and questioned for about 14 hours last Friday, arrived at the CIO building at around 9:40 a.m. Monday and told reporters that she would faithfully answer the questions. 

Yoo is suspected of playing a role in retrieving from the police an initial report from a Marine probe into the death, and reducing the number of key suspects in the case.

The CIO plans to summon more figures involved in the case including former defense minister Lee Jong-sup and Marine Corps Commander Kim Gye-hwan.