I've been hesitant to share my complete thoughts on this, but tonight I think I will. I'll preface by saying it's my opinion only of course. I believe the turning point in my thinking was getting past the shock that a 13 year old girl was abducted.
Digging a bit deeper into what's going on in Barron County, it's obvious they have both a meth problem and an unusually high concentration of sex offenders. Despite what was discussed earlier about Mexican Cartels supplying meth, a quick google search shows plenty of "manufacture and distribute" examples - that's the home grown stuff. And the sex offender to resident ratio is 80:1 in the city of Barron - that's staggering.
I was also surprised at how many of the drug cases I found involved Confidential Informants. There's enough publicly available info to establish Barron County has been cultivating a Confidential Informant program for years and making a concerted effort to infiltrate their local drug underground, something I didn't expect to find in a county of only 45k people. There's even a case where one of their confidential informants was setting up fake drug deals, implicating innocent people and pocketing the money from controlled buys. Dealing with CI's can be tricky, no idea where their loyalties lie and what their motivations are.
But in the case of sting operations that lead back to a manufacturing and distribution network within the local area, whoever doesn't get caught up in the first sweep is left wondering who snitched, what they know, and who else is going to be implicated. This is the situation I believe led to the Closs murders. You've got snitches that can't admit they're snitches and they're eager to point the finger at anyone other than themselves. It could be as innocent as a friend that James had a beer with was in a position to know something. Regardless, there would now be dangerous people with a whole lot to lose that need the snitch silenced.
My theory is that somebody at risk of being implicated in one of these drug raids wanted this killing believing either James or Denise had provided information. Using people not local but already involved in the flow, I'm comfortable assuming that whoever showed up to kill James and/or Denise is already a pretty deviant person and grabbing the girl was opportunistic.
Okay, again - My Opinion Only.