In April 1930, he joined the Schutzpolizei, a branch of the uniformed police under the Weimar Republic and would remain with them after the Nazi seizure of power until July 1934.

It was in this position that he orchestrated the murders by his SS staff of two prominent German Communist Party functionaries, Rudolf Timm on the night of 23-24 January 1934 and Christian Heuck on 23 February.

He led an attack on the Jägerslust estate near Flensburg, a Hakhshara agricultural center that prepared Jews for emigration to Palestine.

After the invasion of the Soviet Union, Möller left his Flensburg police post and was assigned to the Reichskommissariat Ostland which was administered by Reichskommissar Hinrich Lohse who was also the Gauleiter of Schleswig-Holstein.

[6] On 4 August 1941, Möller was appointed the first SS and Police Leader in the Generalbezirk Estland, which comprised the former Estonian SSR with its capital in Tallinn, now renamed Reval.

He left his SSPF position on 1 April 1944 and was transferred to the staff of SS-Oberabschnitt (Main District) Ostland, under the command of Obergruppenführer Friedrich Jeckeln, the Higher SS and Police Leader for the Baltic States and northern Russia, headquartered in Riga.

[2] Möller stood trial for his acts of terror against Jewish citizens in Schleswig-Holstein during the Kristallnacht and was sentenced to three years in prison.

He was also tried and, on 4 December 1947, found guilty of the extrajudicial killing of the two Communist prisoners in Neumünster, and was sentenced to death by the Regional Court of Kiel.