People believe that when a dog bonds to a human, their soul attaches to the human soul after death. Even people who have claimed to have “near death” experiences have reported seeing their beloved pet dog that had already passed.
Paranormal investigators often report hearing a dog barking when there is no dog around to be seen. Some investigators even claim to have captured the image of a dog ghost on camera. Of course, it would be hard to prove an intelligent haunting by a dog, as there would be no real way to effectively prove that the dog was really interacting with the investigator or their questions.