Not sure but I think the perp was able to check in to the room next door and then drill holes in the wall for surveillance cameras or some such.
There is a link earlier in the thread that gives more details.
Apparently he learned (through observation of hotel employees who were up to no good) that one could take out the peephole on the door of the hotel room, and modify it so one can see directly in (remove the fish eye lens). How he was able to remove it while she was in the room, go modify it, then come back and replace it, and then get videos of her, still mystifies me.
But... that's like car thieves. There are people who can unlock a car, and somehow manipulate the ignition to start the car and escape with it. I guess it takes some real skill.
BTW, the scenes in movies where they lean under the dash, quickly pull a bunch of wires out about 1 or 2 feet, then suddenly there are two bare wires they touch together and.... the car starts are completely bogus.