well, they had already talked to the victim's husband, which then lead them to the high school. Yes--the scenes could have been put together in frayed order, but it was that interview that lead them to the school, where Haart gets the radio call, and they both jump in the car, call it in, and even place the blue light on the dashboard as if they are heading to the scene. That's why I can't rationally see splitting the interview with that methead as they did.
I get that I'm missing something here, and that the specific scene of the cabin can be easily separated from that sequence...I just don't see how the undercover operation, capturing the ginger and all that occurs before they visit the school in episode 3--it seems to me that they were still low on information re: Ladeux at that point. I suppose it's possible that we see the ginger capture turning up nothing in the next episode.
I don't think the undercover operation happened then. If you look at that scene after the school, Hart gets back information that Ladeux served time with the victim's husband. They then, jump back into the car, and head to the jail to question him and put out the APB. The scene with, what is presumably Ladeux in his underwear, is simply foreshadowing. They even state in the interview "and that's how we get to Ladeux." possibly leaving the information about the biker gang out, as they might not have put that in the report, to keep as much heat off the undercover operation as possible.
So, the timeline is kind of like this:
they check out the school,
Hart puts in a request about Laduex, gets back he shared a cell for a few months with victim's husband
they put out an APB on Ladeux and head to the jail to question victim's husband again (episode ends with some foreshadowing)
they question husband about Ladeux (even open with "Why did you tell us about Ladeux?") and get information to confirm Ladeux is likely involved
they go after his friend and find out about the bikers
with said knowledge, they go undercover and pick up Ginger (leaving this part completely off the report and out of the interview)