The headline, quoted below, is from a news article which you can read in full here.
Revealed, the dark history of Hitler’s FIRST death camp: How Nazis murdered psychiatric patients – and their nurses – to test out gas chambers before they were used for mass extermination of the Jews
In addition to the Stairs of Death at Maushausen, the Nazis also had another stairs at Fort VII where prisoners had to carry large rocks out of a quarry on a stone carrier like the one shown in the photo below.
The following information is from Wikipedia:
Fort VII, officially Konzentrationslager Posen, was a German death camp in Poland during World War II. According to different estimates, between 4,500 and 20,000 people, mostly Poles from Pozen and the surrounding region, died while imprisoned in the death camp.
The following quote is from a news article about Fort VII, which you can read in full here.
Behind these gates emblazoned with the symbol of Hitler’s dreaded SS, lies one of the lesser known horrors of the Nazi occupation of Poland – the first use of gas chambers for mass extermination.
Seized by the SS on October 10 1939, the 19th century Fort Colomb in the city of Poznan in west Poland was renamed Konzentrationslager Posen (Concentration Camp Poznan).
But rather than serving as a holding space for prisoners of the Reich, what followed was the systematic murder of psychiatric patients, local resistance fighters, academics, the intelligentsia and anyone seen by the Nazis as a threat.
It wouldn’t be until three years later that the use of gas chambers to eliminate the Jewish population became a Third Reich policy.
But 76 years ago this month, it was decided that Fort VII, as it is known, would be the first place to experiment with gas in the mass killing of civilians.
I suspect that the prisoners at Fort VII were resistance fighters, aka illegal combatants. I doubt that these prisoners were pushed off the stairs to their death. But it makes a good story for Holocaust True Believers.