That is actually an 8’ step ladder. It looks like it is fiberglass, a Class II likely. They cost around .... https://www.homedepot.com/s/8‘%20step%20ladder?NCNI-5
You seem to know some about ladders so let me ask you some questions:
If you look at the photos in this article there is a good picture of the ladder:
It appears to be this brand:
https://www.ohiopowertool.com/bauer-ladders-30412
How could someone walking around with a 12 foot ladder be missed?
Did the officer who confronted him climb this ladder? Somewhere it was reported he had to get a boost up from another officer.
Why didn’t he just climb the ladder?
Then he retreated from the shooter.
How did he retreat?
Did he jump off the building?
Why wasn’t the officer in the video of the gunman on the roof?
None of this is making much sense.