Leo Bruls from Sittard was an aircraft mechanic and aviator at the Militaire Luchtvaartafdeling (Military Aviation Department) in Soesterberg. 
Today it is called the Koninklijke Luchtmacht (Royal Dutch Air Force)
After the capitulation of the dutch army in 1940, he became a member of the mine police at the Maurits state mine. But before he had managed to get his hands on a considerable amount of weapons, which he gave to Bartels and Dresen. In addition, group Smit in Heerlen was supplied with weapons. ( Chapter II, p. 100) After a large part of the group Smit had been arrested on February 2, 1942, it was Léon Bruls’ turn on February 17. Sentenced to life imprisonment for illegal possession of weapons and sabotage, murdered in February 1945 while attempting to escape from a concentration camp ( II, p. 116, Appendix V: Arrests in the Smit group)
In his life story at the oorlogsgravenstichting.nl (wargraves foundation)  we read:
In October 1943 he was deported to the infamous Natzweiler camp in France, where the life of a prisoner was worth nothing. Yet he managed to survive there for almost a year. Via Dachau and Gröditz, he was put on transport to the east. Presumably during this journey, around April 20, 1945, he escaped near Dresden. Since then, no one has heard from him anymore.
In Natzweiler he was given the number block 10 no.5630 
He is listed in the “Erelijst 1940-1945” (Honor Roll of the Dutch Parliament).