Another senior military worker was found to have collaborated in a recent hacking incident, officials at the Defense Ministry said Thursday, fueling speculation that military operatives have illegally monitored civilians.

Military investigators also arrested an Army warrant officer on Tuesday, on suspicion of directing two subordinates to hack into emails of a professor at Chosun University in the southeastern city of Gwangju.

The two ― a civilian employee of the military and a sergeant first class ― were arrested by the military authorities last Friday after police in Gwangju found that they hacked the emails and handed the case over to them last month.

The police inquiry opened in early September after the professor reported to a cyber investigation team that some of his online documents had been hacked.

The DSC agents reportedly stated that they hacked his emails as he had a record of violating the National Security Law some 25 years ago. The professor was a key aide to one of the school’s strongest presidential candidates.

Upon receiving the professor’s report, police tracked Internet protocol addresses used in the hacking and found that the two DSC agents broke into the emails with their IDs at an Internet cafe in downtown Gwangju.

The military worker in Seoul turned himself in to the investigators last Friday. The two arrested officers in Gwangju allegedly asked the worker specializing in cyberspace security to assist in the hacking with his expertise, investigators said.

Critics argued that as there are many people with a record of national security law violation, there could be a lot uncovered cases of DSC officials illicitly monitoring civilians.

During Wednesday’s parliamentary interpellation session, Prime Minister Kim Hwang-sik said, “Should the hacking allegations really turn out to be true, it is clearly a criminal act and we should hold them strictly responsible for that. This illegal method should not be tolerated.”

By Song Sang-ho (sshluck@heraldcorp.com)