Throwing Down the Gauntlet

Rizzoli and Isles are on the case of a law student who was killed and dumped into a trash bin. When Jane finds out that Maura knows who her mother is and where she is, she urges Maura to contact her. Maura's biological mother, Dr. Hope Martin (Sharon Lawrence), turns out to be a very successful doctor who helps women and children in need. She invented a technique to help rehydrate the fingers of victims so that they may be fingerprinted for identification. When Maura is in need of that technique, Jane calls upon Dr. Martin for help. Maura decides that she doesn't want to tell Dr. Martin that she is her daughter, since Hope was told Maura died at birth. Angela gets into politics when she starts supporting a new candidate for mayor, Tom MacGregor, Jr., who helps school lunches. Jane finds a link between her victim and MacGregor. It turns out that the new candidate's assistant murdered the victim when she was getting close to discovering that he killed her best friend 10 years ago, because the girl liked Tom better.