This clip was taken while we were chasing footsteps in a housing unit at the Missouri State Penitentiary.  Only three people were present in the entire building and we were all together.  We were chasing footsteps up flights of stairs, past cells repeatedly until we reached the top floor of the cell block.  At that point, they crossed the hall into the adjoining housing unit that was locked and had no access to it at all.  We turned on our audio recorder and as a result picked up singing or music of some sort with a series of repeating notes (that only one person heard at the time) then about 15 seconds later, we all heard footsteps running down a flight of stairs. Without seeing the entity or being able to enter that particular cell block, this sound appeared to be from metal stairs as it made the loud roar that metal stairs make when someone runs down them quickly.  An experienced investigator is heard using profanity immediately afterward as it was very shocking to her.

It won't let me upload both files, as there is a size limit, so I'll just upload the stairs.