...which is one word and not two. (i think i referred to it as "night STALKER" in a comment somewhere. >.< i know the title of the episode, really i do.)
hendrickson does say he's been looking for the boys for weeks, so i was wrong about that (i blame the radiators :D ), and now i'm guessing he's been chasing them since the usual suspects. (how many weeks is "weeks," anyway? five? ten?) if he knows about baltimore he knows about st louis, so he thinks dean's a serial killer ("there is a monster in that bank"), and he knows about an assortment of illegal things the boys have done, and he knows to a certain extent who john was, and all of that is probably info he could've gotten from databases and police reports and secret fbi channels and whathaveyou. my question is how he knows how john raised the boys - cheap motels, backwoods cabins - assuming there is a paper trail, it's likely a bunch of stolen credit cards and aliases. assuming john was smart enough not to use the same card too many times or from one town to the next, how do you track something like that? yes he had to register his kids in school, and if you figure sam had to have enough transcripts and test scores in his own name to get into stanford there's one trail, and i guess hendrickson could've started with john and mary's marriage and moved forward from there, but at some point john had to fall off the grid at least temporarily, and y'all remember a couple weeks ago the cops found those two kidnapped boys in missouri, i think, and one had been gone a few days and one had been gone FOUR YEARS? and wasn't more than a couple hours from where he'd been taken? and had been outside the apartment, had been seen by other people, may even have posted to the message board his parents had set up to help get him back, and no one figured out it was him in the intervening four years. and people were looking. ok, there was no murder involved and the fbi wasn't on the case, but come on, a kid can disappear for four years and surface not far from his parents' house (and only because the cops were looking for someone else), and yet hendrickson can come up with all this info on john's nomadic life in a few weeks? either that's some damn fine sleuthing or he found someone who helped him out. (which itself begs the question - how? i doubt he found the roadhouse.)
and yes, once he knew what he was looking for (john as whackjob survivalist, dean as psycho killer, sam as... uh... bonnie parker) there was a greater chance he'd find it, but come on, you CAN fall off the map. even with two kids and a distinctive black car. maybe not for twenty-three full years (see: school transcripts, and shawn hornbeck not being in school no doubt helped the kidnapper hide him), but you can do it if you're trying.
...oh, wait. i wonder if hendrickson can track them through their cell phone plans. easier to trace where the boys are now than where they were fifteen years ago, but he can probably go back a few years that way. that could also explain how he knew they were in milwaukee.
did that make ANY sense? i'm all with the questions and no theories. i know people have suggested gordon might've given hendrickson some info, and i don't know if i buy it but i don't dismiss it, because i think it's possible (gordon's pissed at sam and dean, he's stuck in jail, he's probably smart enough to figure that if he gives the fbi some info, they can find and maybe take care of sam themselves and maybe get him out sooner). might help answer how hendrickson found the boys, or at least it would've given him a closer place to start looking than baltimore. but it doesn't answer how he'd know about the boys' growing up, because who's alive who WOULD know? he sure ain't been talking to ellen.
and unrelated to the previous, i still love how they shot ronald's death, and the very end, with the song and the boys in their swat gear, that was fantastic.