Experience with Ghosts

This is what a friend of mine said about his expereince with ghosts: "I have had contact with the spirits, even though it may sound pompous, I felt their presence. Once I heard whispering voices  in a place where there was no one else, apart from my friend who was also there and heard the voices too. My sister also saw a ghost in her own house. In a mirror she saw a man dressed in black with a big knife in his hand. When she turned around no one was there".