If you do not have law/contract background then it will be difficult for you to digest international law where criminology is straight forward syllabus, nothing complicated.

https://www.academia.edu/9205567/Cri...logies_Siegel_
here is one and i'll send you the name of other one tomorrow.
I got 69 in criminology, having no background of this type of studies.

Criminology by Muhammad Sohail Bhatii.
This book contain more than enough information about all the topics.
On few topics, the book contain Wikipedia stuff or Research paper material.
Make sure that when you see the research paper material begin in the topic, go and search on internet about that topic.
Make your own notes with the help of this book and internet search stuff.

Good Luck