Melzer spent the next ten years in a succession of prisons. War ended early in May 1945: she was liberated from prison by allied forces on 4 May 1945. She moved to Thuringia where she became head of the women's section with the Communist party leadership in Erfurt. Thuringia had been successfully invaded during the opening months of 1945 by the American army, but under terms already agreed between the allied leaders the area was to be incorporated into the Soviet occupation zone (after 1949 the German Democratic Republic). On 3 July 1945 the American military withdrew, and for the rest of Mezler's time in Erfurt the city was administered by the Soviets.Towards the end of 1946 she returned to Dortmund, now administered as part of the British occupation zone (after 1949 part of the German Federal Republic). Here she joined the party regional leadership team ("Bezirksleitung") for the Ruhr region. She was appointed a member of the Westphalia provincial assembly in 1946, and following a return to democracy she was elected a member of its successor body, the Landtag (regional legislature) of North Rhine-Westphalia, for a three-year term starting in 1947. During her time in the assembly she was vocal in support of equal pay for women and in opposition to the production of more nuclear bombs.