Dr. D., just putting myself in the manager's shoes, he notes problems in the room that necessitates him going into the room. He finds the body and calls the police. He may make note of something like a letter laying out or something like that, but I don't see him going through papers and trying to analyze them.
Likewise the police showing showing up at the scene, would probably deal with the body and gather up any evidence but not spend a lot of time on it at the scene. They may have told the manager something later, but police are well known for not giving out too many details after a suicide. Likewise, if it seems pretty clear cut as a suicide, they don't spend a whole lot of time analysing the paperwork.
From the way the manager spoke, I think maybe there was a paper, not a suicide note exactly as it probably wasn't addressed. But some kind of note. The way it sounds, he seems to be talking about something specific. I am just wondering if the police report mentioned this paperwork.