My cousin was murdered and body parts missing

Since it's an ongoing case I am told we are not allowed to talk about it yet. But I am having sleepless nights and feeling very guilty because I think I might be able to help solve the case but I don't have evidence now. 

My cousin was married to an ex policeman who was very abusive towards her. In public that guy acted like an angel. At first when my cousin opened up to me about the things her husband does to her when no one is looking, I found it hard to believe because of the person that he is around people.

He is down to earth, humble and very soft spoken around people. When he hits her he never touches the face. His favourite place to assault was the back, tummy, armpit and under the feet. 

My cousin sent me pics and also sent me voice notes. He used to abuse her so bad that after beating her up he would order her to walk without clothes in the house and serve him food. He would force her to smile then do the deeds forcefuly.

If she refused he would continue assaulting her. Before killing my cousin he told her not to mess with him because his first wife did that and he killed her and never got arrested. We knew that he was married before but we were told that his wife was found dead in the house. She hung herself while he was sleeping.

That day he admitted that was the day he killed my cousin. After killing her he sent two men to my house to break in and steal my phone at gun point. I know it's him because they took nothing else but the phone.

He must have searched my cousin's phone and found the things she sent to me. This man's mother is a Sangoma who uses muti to always get him out of hot water. The justice system might not belive in witchcraft but it definitely works on the system.

We buried my cousin with missing body parts. We still bump into him living this life like nothing has happened. He walks Scott free like he owns the justice system. 

I am pleading for any Sangoma that can help me deal with this man. I would like to bewitch him, my family and I will pay please don't judge me. We are struggling to heal especially when we see him free.