Dear cperrone,
he is responsible for his own actions, and you are responsible for your own wellbeing!
Apart from that you might even consider yourself having a moral obligation: If you protect him you are giving him a free pass to do all he did to you to others as well! Do you really think there should be a cop on the street who threatens, abuses and hurts people? What do you think will happen if he gets into a secure position within the police force? He would have even more power over other people then!

By protecting yourself you are also protecting lots of other people!

Still, this is not to be taken lightly, and it’s very understandable that you are scared, because this guy is scary! So take good care of yourself, be careful, and try to get as many people whom you trust to help and support you as possible!