Robert Wilhelm Lehnhoff was a German officer of the Sicherheitsdienst (SD) and a convicted war criminal. Born in Mehle, near Hildesheim, he became infamous for his role in the Scholtenhuis in Groningen, the SD headquarters for the northern Netherlands during the final year of World War II.
From September 1944, the Scholtenhuis, located on the Grote Markt in Groningen, served as a center for interrogation, torture, and executions of resistance members. Lehnhoff led the department responsible for investigating right-wing resistance (Referat Rechtsgerichtetes Widerstand). Among his subordinates was the Dutch collaborator Pieter Johan Faber, who was later also executed for war crimes.
Lehnhoff’s methods during interrogations became notorious. His so-called “V1” technique—a brutal blow to the stomach of a handcuffed prisoner using a rubber baton—was feared among detainees. Historian Dr. L. de Jong cited Lehnhoff in his standard work Het Koninkrijk der Nederlanden in de Tweede Wereldoorlog as a prime example of a cruel SD officer.
In the book Verzet in Groningen, Lehnhoff is described as a complex and volatile man—intelligent, manipulative, charming to women, but also ruthless in preserving his own safety.
When Canadian forces approached Groningen in April 1945, Lehnhoff and his colleagues initially resisted fiercely from the Scholtenhuis. As the city fell, the SD group fled via Zoutkamp to Schiermonnikoog, where they hid for six weeks in makeshift shelters at a site called de Eendenkooi. They were later captured and returned to Groningen for trial.
Lehnhoff cooperated with investigators, providing the names of many of his informants. In May 1949, the Special Court in Leeuwarden sentenced him to death. His appeal was denied, and on 24 July 1950, he was executed by firing squad at the Hereweg barracks in Groningen.
He was officially registered as residing in Düsseldorf at the time of his death and was buried anonymously at the Roman Catholic Cemetery in Groningen.
