I didn't blame anybody. Believe me I searched everywhere several times before reporting that I could not find the envelope. I knew I needed a written statement in order to make an insurance claim and the loss must be reported within a certain period of time. So I told the reception desk on my way out to meet friends. They informed security who called the police straightaway and told me that I had to remain in my room.

I didn't mention cleaning staff. The police officer did and I was relieved to hear the hotel security officer tell her that the person who cleaned my room had worked there for something like 15 years and had an exemplary record. I was also glad to know that they could trace which key card was used to open the door and when.

Like the OP I felt so stupid because while this was going on I was practically sitting on top of the missing envelope, which had obviously fallen between the cushion and the frame of the chair. The one place I must have failed to check and the police officer had not checked up to that point. I apologised to the police and security officers for wasting their time and they just said these things happened.