Q. I need to evaluate a criminal case from a specific population (adolescents) and say what assessment and treatment might be effective

I think you are looking for a court case that could be tied into the class textbook (Handbook of psychopathology) by Christopher Patrick. A case that involved an adolescent - one who might be able to be considered by the DSM-V as a "psychopath", based on indicators used from the DSM-V.

Several cases are:

Miller V Alabama.

 Lionel Tate (Tate V State) or 

Alyssa D. Bustamante vs. State of Missouri

You can find these in Westlaw database. Under Databases link, scroll down to select Westlaw, then login with your Saint Leo username and password. You can type these cases into the search box, or just do a topic search.