The Transitional Justice Working Group says North Korea has executed some of its citizens for watching K-pop videos.

The group said it found at least seven executions under North Korean leader Kim Jong Un that were due to individuals watching K-pop, or Korean pop music from South Korea, The New York Times reported.

Kim Jong Un has made possession or distribution of South Korean entertainment illegal and punishable by death.

Six of the seven executions took place in the city Hyesan, which Kim has cracked down on as it is a major trading hub and distribution center for South Korean entertainment.

The six executions took place between 2012 and 2014, when soldiers gathered citizens to watch three officers fire nine shots to kill the individuals, the report said, according to the Times.

The report found the families were also forced to watch the deaths of their loved ones during the executions.

Kim said the influence of K-pop on society would make the country “crumble like a damp wall.”

In the report, the group interviewed 683 defected North Koreans who went to South Korea. They found at least 23 executions have occurred under Kim.

The total could be higher, as it is difficult to get information out of the totalitarian country.

Lead author Ahyeong Park said that “state-led killings continue to take place in ways that may not be as visible to the public as they did in the past,” adding that “what we need to pay closer attention to is non-public killings, such as secret or ‘indoor’ killings.”