As yet another new web page insists that Gilles de Rais must have been guilty because "some time after the trial" fifty human skulls were discovered at the château of La Suze-sur-Sarthe, let us nail this persistent canard once and for all.
There were no skulls, bones or any other human remains found at any of Gilles de Rais' castles at any time. Even Bossard, that fausseur évangile as Prouteau calls him, balked at promoting this myth. He mentions it, but dismisses it as being on a par with the legend of the young girls (girls!) freed from the dungeons. It never happened. And Bossard would have loved for there to have been bones; if there had been, he would have gleefully reported it.
The sum total of forensic proof against Gilles amounted to: -
Some "suspicious" ashes found in the hearth at Machecoul after his arrest. But, as Prouteau says, they might just as well have been from a suckling pig. Ashes are what you expect to find in a hearth.
A bloodied and foul-smelling small chemise found, not at the château, but at the house where Eustache Blanchet lodged along with Francesco Prelati (and doubtless other people.) Hardly evidence against Gilles.
This seems very little to show for hundreds of murders. Where were the severed heads that Gilles was supposed to keep as trophies?
I repeat: there was no forensic proof against Gilles whatsoever. No credible witnesses. And a forced confession.
[Incidentally, the château of La Suze-sur-Sarthe did not belong to Gilles. Perhaps there is some confusion with the Hôtel de la Suze. But that was not a castle, it was a house in the centre of Nantes and would have lacked the extensive souterrains for the storage of multiple cadavers.]