Oh, finally I discovered which one it is. I found the answer by checking some forums talking about Ravenloft and the published modules.
It is in the Book of Crypts anthology, in the module Blood in Moondale. The vampire is Dante Lysin:
Dante Lysin (real name: Dante Curare) is a Nosferatu Vampire and the proprietor of the Moondale Inn. A former gladiator and slave who killed his master, Dante eventually made his way to Moondale and purchased an inn. Over the next several years, nosferatu vampires menaced Moondale. Dante Lysin was one of their victims, drained of his blood and transformed into one of their number. However, when his vampire master was slain, Dante was given free will and concealed his true nature.
Dante hates his condition, but has yet to search for a cure. As a nosferatu vampire, he can live off of animal blood and survive, albeit in a slightly weakened state. However, his undeath is slowly.
Dante Lysin is featured in the Book of Crypts module Blood in Moondale. Over the course of the events in that module, Dante may become implicated as the cause of the murders, though he is innocent.
Thanks all, now it's time to buy it secondhand =)