Who is John J. Riley from A Civil Action and what is their importance?

John Riley is the operations manager of Riley Tannery, a subsidiary of Beatrice Foods, which is accused of contaminating Woburn Wells G and H with TCE. The Riley family once owned the tannery, but, when government officials demand that a water treatment facility be built, the tannery is sold to Beatrice. Riley is an angry, confrontational individual who, during a deposition at Schlichtmann's office, pours a glass of water on an expensive conference table. He insists that his plant never, at any time, dumped any waste materials, despite the aerial photographs indicating otherwise.