Nah, Dutch ain’t a serial killer. It’s obvious the boy did it...he killed his friend, and another boy earlier. He then killed his mom and tried to frame Dutch for it.
Ed
I hope that is what the writers intended - I remember one episode where Dutch was going to do a "Vic Mackey" and plant evidence for a case where he was sure of the perp, and decided at the last minute not to. Dutch always seemed to rise above the fray (except for that cat deal).