Prosecutors said their additional investigation into Won will first be focused on his suspected misuse of state money worth some 7 billion won ($6.19 million) to support about 50 outside cyber teams and their covert operations, both online and offline.

Prosecutors have reopened the case after an internal NIS task force found that as many as 48 such cyber units were operational under Won's leadership, on an all-out mission to oppress those critical of the then conservative government of Lee Myung-bak or on the other side of the ideological spectrum.

The current law bans political interference by the NIS.

The task force has found NIS documents written during those years that show a compiled blacklist of artists and cultural figures unfriendly toward the conservative governments to ban them from appearing in mainstream media. Progressive Seoul Mayor Park Won-soon was also subject to NIS surveillance.

The prosecution said it will also question Won over whether, and how often, he reported to then-President Lee on the cyber smear campaign.

The investigation draws attention as to whether it will eventually target Lee and bring the former leader in for questioning over the ballooning scandal. (Yonhap)