The Case Files of Jeremy Franklin, Teen Lawyer by Jim Watt

Jeremy Franklin is in 8th grade when a friend is charged with stealing a necklace from a locked school locker. Jerry solves the crime and gets the necklace returned by discovering how the locker was entered and identifying the thief in a school assembly. He is praised by a teacher who calls him a 'budding' lawyer. As a result he is immediately asked to represent another student facing expulsion from school. Jerry argues his case in a hearing before the school board and wins. This launches his career as an attorney for his fellow teens.