While investigating at an abandoned school some of the team heard two loud thumps during a communication session held on the second floor of the building. You hear the thumps and then an investigator who was in the hallway outside the room where three investigators were calls out to see if we had also heard the noise. These thumps were so loud and deliberate we wondered if someone was having us on and was banging the wall in a nearby room so we immediately rechecked the outside fire escapes and then went through every room in the building to make sure there was not an intruder. Strangely these bangs were only heard on the second floor and two investigators who had been in the room directly below heard nothing at all. We had many sessions at this school which included checking the attic and never found any evidence of possums or rodents.