Eighty-six Jews had been sent to the gas chambers in 1943 and their bodies brought to the eastern French city of Strasbourg, then under Nazi occupation and where Hirt was assembling a macabre collection of corpses.
The bodies, some intact, others dismembered or burned, were found in November 1944 after the liberation of Strasbourg, in bins filled with distilled alcohol. They were then buried in a common grave in 1946 following autopsies.
But on July 9, historian Raphael Toledano found that some remains were still lying undiscovered at the forensic medicine institute more than 70 years later.
Along with the current director of the institute Jean-Sébastien Raul, the historian managed to identify several of the body parts, including "a jar containing skin fragments of a gas chamber victim".
Test tubes containing the intestine and stomach of a victim were also found.
The remains found at the institute had actually been preserved by a forensic professor from Strasbourg's medicine faculty, Camille Simonin, as part of an investigation into Hirt's crimes.
Simonin had been tasked by the military authorities with carrying out judicial autopsies in order to "establish the conditions that had led to the death" of the victims.
Toledano was given a clue as to the location of the remains in a letter written by Simonin in 1952 that "mentioned the jars containing the samples taken in the course of judicial autopsies carried out on the Jewish victims of the Struthof gas chamber".
"The labels identify each piece with precision and mention the register 107969, which matches the number tattooed at the Auschwitz camp on the forearm of Menachem Taffel, one of the 86 victims," said the statement announcing the bodies' discovery.
Local authorities plan to return the newly discovered remains to the Jewish community of Strasbourg.
They will be interred along with the rest of the victims at the cemetery of Cronenbourg to the west of the Alsatian region.
Hirt committed suicide in July 1945, before the Nuremberg trials.