I spent some time watching the surveillance video in very slow motion and making notes. Of course, this could all have been covered before because I have read much of these threads but not all of them.
0.28 - As perp comes out from behind the door, the hammer is in his/her right hand and he/she raises it to about waste high, almost as if he/she is motioning to someone.
0.49 - Perp is messing with the locked door and is swinging the hammer (awkwardly) with his/her left hand.
1:08 - 1:10 - Perp adjusts himself/herself near the right shoulder. As he/she walks away, the hammer is still in the left hand (as he/she rounds the corner near Common Grounds)
1.22 - At the dutch doors, perp opens the door with his/her right hand and the hammer is in the left. Steps/leans inside the room
1:34 - Perp comes out of the dutch door room without the hammer in his/her left hand. It could possibly be in the right but hard to tell. As perp walks past the dutch door room and down the hall, he/she stops at another door and I don't see him/her go any further down the hall.
1:40 Recording jumps to perp walking back up the hall and hammer is in the right hand.
1:59 Perp walks through the door with #12 on it and hammer is in the right hand. The white object is in his left hand. He/she swings with the right hand this time.
Also, the perp appears to pick his/her entire foot up each time and sets it down flat; does not lead with heel. It's as if he/she had on swimming fins on.
I am beginning to entertain the idea that there are two people on the video.
All, JMO of course.