According to Yun Dae-il, who once belonged to the North Korean secret police “National Security Service”, North Korea has an organization called Anjeonsojo(meaning small group for safety) to monitor residents.

The Ministry of People’s Security has created an organization called “Anjeonsojo” among its residents, through which many spies collect information as well as materials about personal life. (Yun Dae-il, “North Korea National Security Agency”)

“The Ministry of People’s Security” is a government agency that controls police in North Korea, and has a network of organizations from the center to the terminal administrative divisions such as “do”, “city”, “gun”, and “ri”. Has been around.
Regarding the activities at Anjeonsojo, North Korean defector Yoo Yong testified as follows.

My father kept secret that the maternal aunt and his wife had fled to Korea from January to April 1951 during the Korean War. If their relatives are Vietnamese, their loyalty to Kim Il Sung is considered to be low, and their ingredients will deteriorate.
However, in 1984, the National Security Service conducted a resident survey, which caused the family to be banished to Mt. Cherry blossm in Hamgyongpuk-do. (…) In high school, when the ingredients were still good, I was the one who monitors and informs those exiles. At that time, there was a secret organization called Anjeonsojo in each region, and I was a core member of it.
Ten to fifteen students per school will be selected, surveyed by residents and reported at weekly meetings. His main job is to monitor political prisoners who have been expelled from executives.
A pair of people stood all night at the window and watched for Korean broadcasts on the radio. Since the child was not suspicious, it would have been convenient to monitor the residents. (“Exiles from North Korea”)