Who is Larren Lyttle from Presumed Innocent and what is their importance?

Larren Lyttle is the presiding judge at Rusty's trial. A former partner in a law firm with Raymond Horgan, he remains one of Horgan's best friends. Lyttle is a large black man with a face full of guile and majesty. An extremely imposing figure, he treats reporters well and has the gift of captivating a jury with his personality. A former defense attorney, he likes to joke in court at the expense of the prosecution and is not above referring to race as a way of bonding with black defendants who await their turn to face the bench.