South Korean prosecutors say they will indict the former head of the country’s spy agency for attempting to influence last year’s presidential election.

Won Sei-hoon, the former director of the National Intelligence Service, is accused of ordering agents to post stories and comments in favour of Park Geun-hye online. An official investigation found that the NIS posted comments using more than 100 identities.

Opposition presidential candidate Moon Jae-in was defeated in the tightly-fought December 19 vote.

Although it is not clear whether the alleged campaign influenced the outcome of the vote and there is no evidence that Park knew of its existence, reports BBC.

Prosecutors say Won, who headed the NIS for four years until 2013, had “systematically and extensively intervened in domestic politics”, violating election laws, South Korea’s Yonhap news agency reported. Won reportedly denied the charges against him.

The prosecutor’s office said that while Won would be indicted and cannot leave the country, he will not be physically detained.

Kim Yong-pan, the former head of the Seoul Metropolitan Police Agency, will also be indicted for obstructing the police probe into the case, according to prosecutors.