Hey Gasman, you know me - have to be Devil's advocate - the 'ghost' at Eastern State - um, probably not so much. It's in a pretty rough part of Philly (I did some archaeology there) and lots of kids (and adults) still break into the place at night to goof off. There's no real security around and there are lots of tunnels in and out of the place not to mention climbing over the walls via the trees around it and such. I was impressed at first but then, I dont' know any ghost that where white sneakers

. I imagine what happened was some drug idiot broke in, was running the corridors, saw the blinking light on the camera and thought 'crap, surveillance' and ran.
Now... the figure on the storage cabinet in another ep (can't remember where) - now THAT was, in my opinion, absolute proof. There was no way that could have been accidental or anything, especially the way GH checks and rechecks, well Jason and Grant anyway

.
But Eastern State Pen most likely just a drug dealer or someone.

Yes, I have such pride in my city *cough* *cough*