Why does it matter if this is really why he was caught? The facts are that he was caught, and there was a legal way for him to have been caught. That's why parallel reconstruction is acceptable in the first place.
That's news to me. Does anyone find parallel reconstruction acceptable in any situation whatsoever? HN gave me the impression that it's never good and a strong indicator of corruption and/or lying. Am I wrong?
The ideal course of action would probably be to admit all the evidence and then prosecute both the suspect and the bad cops for their respective crimes, but that's cost-prohibitive and for minor offenses even being prosecuted in the first place is often too much punishment. So as usual we end up with the courts accruing increasingly complex justifications to strike a compromise where one is needed, but the compromise the courts manage to justify isn't always a good or sensible compromise.
Really, there should be some personal liability for the police when they do something illegal to catch a criminal. That change isn't going to happen.
Also, "Making and selling certain chemicals." is something that shouldn't be illegal in the first place.
When it's Alan Turing and stopping the Germans from realising an Enigma message has been read by the global surveillance apparatus of the Allies and been broken, by sending out a Catalina to look for a U-Boat at just the right time, that's great and an uplifting exemplar of the way things should be.
When it's an email that's been read by the NSA surveilling Internet data, that is then used to tell the DEA to go and stop a car at just the right time to catch a cartel drug courier and murderer, that's not?