On the 20th of October 1944, the 4th Canadian Armoured Division, the 49th British Infantry Division, the 104th US Infantry Division and the 1st Polish Armoured Division attacked on a broad front towards West Brabant. This operation was named Suitcase. The aim was to cover the flank of the Canadians advancing towards Zeeland and drive German troops out of West Brabant.

The Americans of the 104th Infantry Division, known as the Timberwolves, crossed the Dutch border south of Achtmaal. It was the American troops first battle. Achtmaal constable Lambert Vermeer, a member of the underground, approached Lieutenant Colonel Kelleher. He handed Kelleher a package with information about the German defences that proved to be very useful.

The Timberwolves liberated Achtmaal on the 27th of October 1944.