Riley is a character mentioned briefly in the Bright Falls miniseries.
In the Bright Falls mini-series, Hal reminded Jake Fischer he needed to get the book The Creator's Dilemma signed by Dr. Emil Hartman. Riley probably gave his book to Jake, because he was going to Bright Falls, the town were the author of the book resides, it could also be a present for Riley from Hal.
Bright Falls (Mini-series)
Riley's only appearance is in that of Bright Falls. Even then his name is merely mentioned.