How Do I Go About This?

I'm a 24 F and I have had issues with processing my trauma. I was left alone and molested at 6 by a friend of my mom's druggie friends and didn't tell my mom about it until I was 9 when my friend told me to tell my mom. I didn't tell anyone because he knew where we lived, he knew when my dad would be gone, and he nonchalantly told me that I look like I could fit in his trunk when he was showing me porno magazines. I told my mom and she only hugged me and just went on about her trauma her family. As if its nothing and it just happens. I waited for her to do the right thing and to contact police and never did. I asked her if she knew him and what his name was and only said she knew him as Mike (he told me his name was Jack) Fast forward to now, it's killing me every single day and don't know what to do because I wanted him to be brought to justice so he wouldn't harm others and the guilt is hurting me. Everytime I see my mom it kills me because I could've told a teacher... A doctor... But instead, I told my mom.... How can I bring this man to justice if I don't even know his name....