Our minds seem to be traveling somewhat the same paths. Unsavory characters, prostitutes, young women who are illegal immigrants might all fit into the "invisible" community Otto has mentioned. The first two are long-time prey for SA predators -- often never even reported as missing. The illegal immigrants, of course, can not be reported as missing -- or at least are not likely to be reported. Anyone abducting/killing them is basically safe.
From the beginning, I have thought that if CR is experienced and MT was a SA abduction, then his experience was gained on young illegals. I doubt he would do an SA abduction of cougars he might have encountered.
No, he seems to have a type -- and that is my conclusion based on very scant facts. But IM and MT are all we know at this point and they have certain resemblances.
We really, really need to know where CR lived before Brooklyn. AND we have to wonder, even if MT is his type WHY IN THE WORLD would be grab someone as visible as MT when there are so many "safe" women he could grab.
Without a suitable answer to that question, I find I am leaning toward CR being a beginner. Of course, that's at this moment. Might be leaning the other way this afternoon.