Well.
Some of my students know others who kill animals in the neighborhood (chickens, turkeys, goats) even though it is TOTALLY against the law where we live. Others have someone living in their home who is raping family members, but they are afraid to tell anyone - except in the most quiet of ways and certainly not directly to LE.
These people are indeed regarded as monsters by their relatives and friends who are in the know, but are unlikely to be the perp here (turn them in for what they are already doing, of course).
A young man in my county repeatedly ran women off the road, and either raped them or just injured them and their cars. He chose increasingly deserted and dangerous places to do this. He was out all night. He had a sibling and friends to whom he bragged (not with all the details, but enough). That's how he was caught. They knew he was a monster. This perp could be one of those - or he could be someone that would surprise nearly everyone.
I think the perp in this case will surprise his closest associates (whom he may have chosen in a certain way) but he is unlikely to be bragging about his criminal activity or recruiting criminal associates, if you know what I mean.
He's not that guy who approaches cars at the stoplight or yells frantic things at young women students or sexually assaults younger family members. IMO.
Think "doesn't torture and kill animals." HOWEVER, I will admit that I am following along with what LE has already said, in this regard. If I'm wrong (and this perp is your basic local sociopath) I still think he's very well hidden and that his family and friends/teachers will be shocked.