For me, the answer is an unwavering YES!
I'm his brother or father or Uncle...whatever, my job is to support and love my family members. I'm not the police. Its the police's job to catch him.
There is one factor that would make me turn him in. If i'm pretty sure, if my brother was loose, he would commit the crime again.
I'm not condoning killing. I'm 100% against any man killing another man. But that is a "action". Once that happens he is still my brother. If I turn him in, I've just killed my brother. He would be sent to prison or executed.
We all have roles to play. My role as a family member is to love another family member. Unconditionally.
Suppose my brother is very anti abortion. He bombs a clinic and kills someone. I maybe horrified and my personal views on abortion are different from his. His action is wrong. But he is still my brother. He killed a man. But i'm not about to kill my own brother for his evil act.