What are my rights as an employee?

About a month ago, I noticed my co-worker was coming to work with a gun strapped to his ankle. I told my manager because I was concerned for mine and others safety. (this guy has a wicked temper and flies off the handle frequently). They ended up allowing him to "resign respectfully". However, they just re-hired him. He knows that "several people" told about his gun...and keeps trying to find out who told on him. I feel unsafe...and am wondering why my employer would re-hire this person. As an employee who feels unsafe and violated...and has already gone to my employer once when I saw the gun...what are my rights? - Is this your question? Add additional information