Who is Richie Pembleton from The Abduction and what is their importance?

Richie Pembleton is Aiden's closest friend. When Aiden returns to school, he isn't sure what to expect. Richie lets Aiden know that he is there for him, and he even goes so far as to put his life on the line to help Aiden. It is because of Richie's actions that Aiden is finally able to open up and trust people again.