Looking around, both Veroth and Roland will find the place free of traps (more Veroth than Roland), they'll also notice a fully equipped alchemy lab (the non-travel version) in the north-west corner, on a workbench. In fact, it looks to be of masterwork quality (+1 circumstance checks on Craft: alchemy). In the crate nearby, you'll find what seemed to be the equipment of the two deceased Lightbringers (a half-plate, a chainmail, a greatsword, 2 spell scrolls, and their Lightbringer insignias).
Looking at the clues, roland conclude he used the information on the torn page which was found on the altar above to create the blaspheme. More than likely this included the use of the alchemy lab as well as the large metal slab to hold the creature until everything was done. Now, where Danovich found this blasphemous document and if Strahd facilitated it,s discovery, he can't say...