I had a short term job that I was fired from. I was told that someone tripped and was injured on something I left laying around, which in fact I didn't do. As "proof" my manager showed me images of images and a message. I won't get into the details but the "proof" is just ridiculous, the floor in the photo doesn't even match where the event was claimed to have happened. It would seem that my coworkers heard I was fired for this.
Is this defamation? When I asked management why they believed I did this they just say "someone told us".
Another way to phrase the question: does a employer have a responsibility to make some effort to determine if an accusation is true?