According to Tom Fontana, Ed Begley Jr. is indeed playing his character Dr. Victor Ehrlich character from Fontana's previous show St. Elsewhere (1982). He is not mentioned by name to avoid having to get legal clearances.
Det. Meldrick Lewis: Luke Ryland snuffed two women live on the Internet. And Baltimore being Balto-less, he got off on a technicality. Next day, they found him curbside, laying there, .44 slug in the back of his head.