In January 2012 Carl and I investigated the Marlboro Psychiatric Hospital in Marlboro Township, NJ.  The facility closed over 10 years ago and in the process of being torn down.  It's a beautiful campus with over a dozen two story buildings.  While investigating the campus we placed a static High Def video camera in Building G.  We let it record for over an  hour.  There were several loud bangs and what sounded line someone walking behind the camera.