Some hotels have a log of who & time of when the housekeeping goes to clean up the rooms. That's one way to check. Unless you know roughly what time you discovered the theft, then they can go thru the log if they have one. Most likely suspect is the housekeeping. This happens almost at any hotels big or small, 1 star or 5 stars. Never leave your prize possessions or valuables in the hotel rooms unless you keep them in the safe. Trust no one
One suspect is the house keeper, of course.
The house keeper usually leaves the door open when you are cleaning the room, so to 'prove' to people they are not stealing things. Once I returned to my room while the house keeper was still around. She did not request me to wait outside (courtesy I suppose) and let me enter the room. Imagine a random person walked in, claim he/she stays at the room, he/she can then take things out from the room very easily.