The Cook County state`s attorney`s office has begun investigating Michael P. Fontana, a Chicago man who worked as a lawyer for 10 years without a license, according to sources familiar with the inquiry. Fontana was fired April 25 from the firm of Sonnenschein Carlin Nath & Rosenthal after he admitted that he failed to graduate from law school, never passed the bar exam and was not licensed to practice law. Practicing law without a license is a misdemeanor violation of state law with a maximum penalty of one year in prison.