Some of Napier's neighbors accused him of being a sorcerer and in league with the devil, believing that all of the time he spent in his study was being used to learn the black art. These rumors were not helped by Napier when he used his black rooster to catch a thief. Napier told his servants to go into a darkened room and pet the rooster, which had been colored black by covering it with soot, claiming that the rooster would crow if they were the one who stole his property. When the servants emerged, Napier inspected their hands to find the servant who was too afraid to touch the rooster.