Prosecutors on Thursday raided the houses of two former agents of the nation’s main intelligence agency and one informant as part of a widening investigation into allegations that the organization attempted to influence public opinion ahead of last year’s presidential election.

The scandal centers around allegations that the National Intelligence Service extensively and systemically meddled in the presidential election by using its agents to post a slew of politically sensitive comments against the opposition candidate on the Internet to sway public opinion ahead of the December race.

The three are under suspicion of leaking private information and informing the main opposition Democratic United Party of the alleged political intervention, prosecutors said.

A team of prosecutors and police investigators seized the spy agency’s internal documents and cell phones from the three people’s houses, they said.

The two former agents, surnamed Kim and Cheong, were dismissed from the agency after a tip-off to the DUP about the scandal, prosecutors said.

By law, NIS agents are barred from leaking any information they have acquired on duty and may face up to 10 years in prison or receive a fine of 10 million won ($9,090).

The three people in question, who have been barred from leaving the country pending investigation, will soon be summoned for further questioning, they added.

The raid comes just two days after the headquarters of the NIS in Naegok-dong on the southern edge of Seoul was raided as the probe has been picking up pace. (Yonhap News)