Yeah sorry, you have simply just made that up.
"But is shows..."
Firstly, you have assumed that an intruder brought in the rope.
Secondly, you have assumed that said intruder planned to use it.
Thirdly, you have assumed that having brought it in, the intruder decided not to use something that you assumed he was going to use.
Fourthly, you have assumed it was left behind because of some risk involved in returning to get it?
Sure, you say "I have no idea", and that is the only correct statement in the entire post.
I suggest that for a thread that only wants to stick to facts, and I'm all for that, this is not sticking to facts.
Carry on.