Legal thrillers usually culminate in a coutroom drama, in which a lawyer or other legal professional is featured as the supreme hero of the proceedings. Often, a young, still unexperienced lawyer is fighting against an overwhelmingly powerful opponent - ultimatly succeeding in the protection of an innocent against injustice.
Many courtroom dramas are written by former legal professionals, who are familiar with the intricate details and technical terms of legal proceedings. Examples are the lawyers and authors Scott Turow and John Grisham. More on Wikipedia
Probably the most famous legal thriller is Harper Lee's "To Kill a Mockingbird", in which the six-year-old Jean Louise Finch tells the story of Atticus Finch - her father and a middle-aged lawyer. He is appointed to defend Tom Robinson, a black man who has been accused of raping a young white woman. To Kill a Mockingbird is probably the most widely read book dealing with race in America. The book is widely taught in schools with lessons that emphasize tolerance and decry prejudice - but it is also a thriller, full of complexity and horrors.More on Wikipedia