My company retaliated against me for reporting an assault in my backroom and today I was suspended.

I am a store manager at Goodwill. I complained about an employee being aggressive and violent. The employee was allowed to return where he assaulted me in the backroom with a back vibrator on camera with another store manager as a witness. I again reported it. This employee had a attempted murder charge and an assault charge on his record and was attending anger management classes. This was reported to H.R. I received no response, so I called in sick the day he was supposed to return and they terminated him. (his termination reason states that he was terminated because Goodwill felt his previous criminal record did not make him a good match). No mention of my complaints. I was given a corrective action and a performance improvement plan immediately and today I was suspended.