8:33 AM just walked up turn the alarm off in the building and something is banging away on the wall above us. We can hear it from outside, before we even enter to shut down alarm!
Yesterday I was walking out of the building with a new hire, and I hit the wall three times and something responded three times then the new hire did it and responded again total of three separate knocks coming from right next to the hallway and we were standing in 1st floor North end, by bedroom #2 entry door..