Did montresor stab fortunato

In "The Cask of Amontillado," Monstresor intimates that he and Fortunato have been friends, or at the very least, intimate acquaintances. Their conversation implies they at least have some sort of a relationship, because Monstresor knows he can lure Fortunato away by the promise of a rare wine, and the mention of another mutual wine connoisseur friend, who Fortunato considers a rival.