A group of four South Korean activists accused of spying for North Korea are believed to have indirectly reported to the North on the investigation against them through a local newspaper.

According to Yonhap News Agency on Monday, the revelation was made by the Cheongju District Prosecutors' Office during last week's hearing on court warrants to arrest the activists.

Stating that they had informed the North's espionage unit of their charges and the exposure of a North Korean spy's identity, prosecutors argued for their arrests, expressing concerns they would destroy evidence. Arrest warrants were issued for three of the four activists.

The group faces charges of violating the National Security Law, for allegedly taking orders from Pyongyang and conducting protests against Seoul's plan to bring in U.S.-built F-35A stealth fighter jets.

After a raid of their offices and residences by the National Intelligence Service(NIS) and the National Police Agency(NPA) in May, the group is thought to have resorted to a local paper run by one of its members to indirectly inform Pyongyang of their plight.