But according to this--unless Joe and Roderick are pretending not to know each other (which I first suspected but then tossed aside by the end of the scene)--Joe sought out Roderick after discovering he was a dirty cop. According to this, Roderick didn't even go to school at Winslow, let alone was he in one of Joe's classes. Furthermore, I always assumed that, after Joe was put in prison, he and Roderick schemed and figured out how to get Roderick into the Havenport police department specifically to protect the area around that mansion (and so Joe would have allies in law enforcement positions). I thought Roderick becoming a police officer was a direction reaction of Joe getting arrested. (Also, it was always kind of suspicious how quickly he rose up through the police ranks to be sheriff at such a young age.)
But (!) if we follow this scene, Roderick was already a cop when he met Joe--probably for many years prior--and had either just begun abusing his power or Joe had just begun noticing it. (I imagine he'd been doing it for a while, but Joe had only recently taken notice because his own 'dark passenger' (to steal the phrase from Jeff Lindsay) was starting to take the wheel.) According to this, they were two separate psychopaths who linked up; sure, Joe taught Roderick some things, but they have nothing close to the student/teacher relationship I'd always assumed. However, I don't think this really changes how close they are--Joe still came into his life at what was probably a troubled, and seemed to help him channel his rage/urges in less noticeable patterns.
Anyway... I just finished a final and yet this is what blows my mind. Happy Friday!