Since its pilot episode, Will Trent has had the same main cast, but that finally changes in season 3 when a new (and familiar) face is added to the roster. The ABC crime drama show is based on Karin Slaughter’s book series of the same name, revolving around Will Trent, a highly skilled GBI (Georgia Bureau of Investigation) special agent with a troubled past. When Will Trent begins, Will is many years into his job, surrounded by his loved ones, coworkers, and beloved pet chihuahua. Unfortunately, his relationship with all of them (excluding his dog) is strained to differing degrees.

https://screenrant.com/will-trent-season-3-cast-character-guide/