Main opposition Liberty Korea Party lawmaker Choi Kyung-hwan returned home Thursday morning after 20 hours of questioning by prosecutors over bribery allegations.
The former finance minister and deputy prime minister under the Park Geun-hye administration is accused of receiving 100 million won from the National Intelligence Service(NIS) in the name of "special activities funds" in 2014. 
The four-term conservative lawmaker was investigated as a suspect at the Seoul Central District Prosecutors' Office from around ten a.m. Wednesday to six a.m. Thursday.
He is known to have strongly denied charges that he took money from the spy agency.
He told reporters on his way home that he sincerely faced questioning. 
Prosecutors  who are looking into the scandal involving improper use of NIS funds sought to grill Choi after securing testimony from former NIS chief Lee Byung-kee. Lee told investigators that he approved the delivery of the 100 million won to Choi after accepting the suggestion made by former NIS planning and coordination office chief Lee Hun-soo. 
The prosecution will analyze Choi's statement given during the questioning and mull whether or not to request an arrest warrant.