Klaipėda Region
In 1933, Bertuleit joined the NSDAP. He became a deputy of Neumann and was tried for anti-Lithuanian activities during the Neumann–Sass case (December 1934 – March 1935). He received a twelve-year prison sentence but due to the German pressure was released from the Lithuanian imprisonment on 14 February 1938. When December 1938 elections to the Parliament of the Klaipėda Region elected a pro-German majority, Bertuleit was appointed as the President of the Directorate of the Klaipėda Region. After the March 20, 1939 ultimatum, Lithuania had to transfer the region to Germany. Bertuleit participated at the signing of the transfer treaty in Berlin and coordinated the transition until August 1. As the Directorate and the Parliament of the Klaipėda Region were liquidated, Bertuleit became a member of the Reichstag on April 25.