In 1955 Olesen was part of the CIA team who secretly listened in the leftist politicians Ragnhild Andersen and Alfred Jensen. He also worked in a private intelligence organisation called Arbejdernes Informations Central (Danish: Information Centre of the Labour Movement) financed by the labour movement.
During 1955, Olesen was involved with the CIA group that covertly listened to leftist politicians Ragnhild Andersen and Alfred Jensen. Additionally, he contributed to the Information Centre of the Labour Movement, which was privately financed by the labor movement.