Pierre Coenen and his brothers, the most famous of whom is Sjeng, who was shot on the Cauberg in Valkenburg, played a leading role in the resistance movement in the Gulpen-Simpelveld region.

Early in the war, they became involved in helping French-speaking prisoners of war who had escaped from German internment camps. Later, these PoWs were joined by allied pilots, people in hiding, and all kinds of refugees. Pierre received the prisoners of war from his brothers in Simpelveld and a liaison officer in Gulpen. He put them up in the coal cellar of the parish house, after which he accompanied them to Belgium with the help of a resistance group in Slenaken and handed them over to Belgian contact persons.