Evidence Montresor planned to kill fortunato

In Edgar Allan Poe's classic short story "The Cask of Amontillado," our narrator Montresor kills a man named Fortunato as a form of revenge. He does so by luring Fortunato into his catacombs, under the false pretense of allowing him to tast a rare type of wine called Amontillado. When they reach a sort of small crypt, Montresor puts a drunken Fortunato in chains and builds a wall, sealing Fortunato into the catacombs, and leaving...

In Edgar Allan Poe's classic short story "The Cask of Amontillado," our narrator Montresor kills a man named Fortunato as a form of revenge. He does so by luring Fortunato into his catacombs, under the false pretense of allowing him to tast a rare type of wine called Amontillado. When they reach a sort of small crypt, Montresor puts a drunken Fortunato in chains and builds a wall, sealing Fortunato into the catacombs, and leaving him there to die. 

The fact that Montresor specifically tells us, in the very first line, that he planned to take revenge against Fortunato, can act as evidence that he planned to kill him. He also tells Fortunato that his family motto is "Nemo me impune lacessit", which essentially translates to "no one crosses me and gets away with it." However, probably the most solid piece of evidence showing that Montresor planned this killing is that he takes a trowel down into the catacombs with him. He uses this tool to build the wall that traps Fortunato, so his bringing it definitely shows that he planned to kill Fortunato in exactly this way.