Did Elisa Lam know the killer?

Logically speaking, she most likely knew the killer...why you ask? 1. She jumps/hops out of the elevator to show signs of 'relieve' 2. She appears to be talking to someone 3. She drops her hands after talking 4. Finally, why kill her if the killer 'knows' she will never go back to Cecil? The logical reason is that she CAN recognize the killer and the killer lives in the 'hotel' long term and does not want to be captured. The residents and hotel staff will most likely know where all the cameras are as well. Sadly, the residents and hotel staff are all under watch.

Why Didn't Elisa Lam Wear Her Glasses

That came across to my mind ...why didnt she wear her glasses...A thought occurred to me that it is possible that the 'murderer' had the key to her room and tried to open it and she heard.  She probably just hid in the closet next to the door and when the 'murderer' went inside the room, she 'slipped out' without her glasses... if she was wearing contacts, it will be apparent since she needs 'liquids' and a case to store them...If she wasn't wearing contacts, I will be convinced that someone has the key to her room...just another theory...what do you think?

Security Guard or Staff?

This post is an opinion rather than a list pictures. My friend invited me to his apartment today and his building has a security camera that points directly to the front lobby, but similar to the Cecil you can hide at the corner without being seen by the camera. For 'role play' purposes, I experimented 'hiding' at that spot, but was unsure whether I can be seen. The only way I can be sure is to check the camera logs. Thus, I'm sure the murderer had to do the same and had access to the cameras before hand. Additionally, to access the roof, and lockout the elevator, you would need special keys only staff or security would have.