Why is it fair to let someone get away with workplace violence and what can you do about it?

theres this crazy older lady in our department who has been there for 40 yrs, she is very close to the director and she is just bananas! she yells at customers, will follow them, curse at them and even make death threats and at one time even lunged at another employee with a knife. When reported, the cops were called, etc, instead the person that she threatened, he was told that if he didnt drop the case, that he would be fired and get in trouble just because he had a record and didnt put it all down on his application (which was his wrong doing)..however there were many witnesses to what happened and still it didnt matter. Also, instead the cops and such were saying that they mustve been all plotting against her so instead turned it around on the guy that she made threats against. She has been reprimanded, talked to and still continues.....I know this is all about politics..but why is it that that perps have more rights and get more leniency and get away with anything and the victims are the ones that pay the penalty? What can be done about it?