The trial of Heinrich Tillessen was held in post-war Germany, and received widespread attention from the public and from legal experts, exemplifying numerous problems in the judicial processing of crimes committed before and during the Nazi period.

Tillessen grew up with ten siblings (three brothers and seven sisters) in Cologne, Metz, and Koblenz - the garrison locations of his father.

Following the death of his father and mother (1910 and 1911), Heinrich Tillessen left high school and joined the Imperial German Navy as a midshipman on 1 April 1912.

After the group disbanded, Tillesson attempted to undertake a civilian job, and on the advice of his brother Karl, accepted a position with the Bavarian politician Georg Heim in Regensburg.

During his employment, Tillesson became increasingly radicalised within the environment of the Deutschvölkischer Schutz- und Trutzbund (German Nationalist Protection and Defiance Federation) and the political leanings of Heim.

However, under the continued leadership of Hermann Ehrhardt, the brigade re-formed in Bavaria to create its successor group entitled the Organisation Consul (O.C.).

On 26 August 1921, during a walk with a fellow Reichstag deputy and member of the Center Party, Karl Diez, the two assassins ambushed Erzberger in the Black Forest near Bad Griesbach.

In Budapest, they assumed new identities,[3] and joined a Freikorps supported by Miklós Horthy's national army, whose protection they had been promised during the early stages of the assassination plan.

[7] With the assistance of his political associates in Germany, Tillessen then acquired a fraudulent German passport and travelled to Spain at the end of 1925.

After Adolf Hitler was appointed chancellor on January 30, 1933, President Paul von Hindenburg signed the so-called Straffreiheitsverordnung (i.e. e. Impunity Regulation) on March 21 of the same year, the first paragraph of which states:"Impunity is granted for crimes committed in the fight for the national uprising of the German people, in preparation for it or in the fight for the German soil (...).

During the Second World War, Tillessen served the German Admiralty in a land-based role and was eventually discharged in late 1944, with the rank of Lieutenant Commander.

Following the occupation of Heidelberg by American troops on May 3, 1945, Heinrich Tillessen was apprehended in response to reports of his affiliation with the National Socialist Party.

"[8] The prosecution presented an appeal to the Higher Regional Court in Freiburg on September 13, 1946, and argued the Straffreiheitsverordnung decree was declared void by the Allied Control Council and military governments, as it was deemed to be an injustice from the National Socialist regime.

The trial took place in November 1946, during which the prosecution called for a death sentence to be imposed, while the defence argued for the accused's exoneration, citing the Impunity Regulation of 1933.

Consequently, the chairman of the examining tribunal, Regional Court Director Goering, was removed, and given a leave of absence, before officially taking retirement.

The French Tribunal général du Gouvernement militaire de la zone française d'occupation en Allemagne (GMZFOA), located in Rastatt near Baden-Baden, was the supreme court for all civil matters in Baden during the period of the Allied occupation in the aftermath of WWII.

In December 1946 and January 1947 the tribunal conducted proceedings to determine the legal validity of the 1933 Regulation on Exemption from Punishment (Straffreiheitsverordnung) adopted by Adolf Hitler, following the end of the war.

Additionally, in March 1958, at the plea of Matthias Erzberger's widow, the remaining sentence was commuted to time service, on grounds of mercy.