The anti-corruption investigation office questioned a former chief of an investment firm Friday as part of its investigation into alleged political interference in the military's inquiry into the death of a Marine conscript, sources said Friday.The Corruption Investigation Office for High-ranking Officials (CIO) questioned Lee Jong-ho, former head of Blackpearl Invest, the previous day as a witness, the sources said.The CIO is currently investigating allegations that the presidential office and the defense ministry inappropriately interfered in the Marine Corps' inquiry into the death of a conscript, surnamed Chae, who was swept away during a risky search mission for victims of heavy downpours last year.A series of mobile messenger and phone conversations published by news outlets has since raised further suspicions of illegal lobbying to exonerate Lim Seong-geun, the commander of the Marine Corps 1st Division at the time of the accident, from involvement in the Marine's death.Lee has been accused of being at the center of the alleged illegal lobbying. In one phone recording from last year, Lee was heard saying, "I will talk to the VIP," and claiming that he dissuaded Lim from stepping down over the case.During a recent news interview, Lee said that "the VIP" was referring to first lady Kim Keon Hee, but he claimed he is, in fact, not on speaking terms with her.Lee is currently standing trial in connection with alleged stock manipulation of Deutsch Motors Inc., in which the first lady has also been accused of involvement.During Thursday's questioning, Lee reportedly claimed he told a lawyer last August he will talk to the VIP because the lawyer induced him to made the remark.Source: Yonhap News Agency