Lawful evidence gathering doesn’t require you to know the answer to every question you want to ask someone up front. Nothing would ever get solved if investigators couldn’t act on the perfectly logical conclusion that the suspect must have talked to SOMEONE to get this part of the crime done, and this SOMEONE ELSE knows who that was.

The balance is in tailoring the access that the investigators have to the SOMEONE ELSE. They have to convincingly demonstrate the connection between the questions they want to ask the third party and their ability to legally use that evidence to further their case.

It’s like saying the cops can’t subpoena the taxi dispatcher because the suspect only ever talked with the driver.

The case is against EZLynk, not the folks using the product.

> The question is, how did the investigation got started, unless they already can see that people are misusing the product? And since they obviously must be able to see that people are misusing it, why don't they instead obtain evidence about those specific users, that they must have observed already?

Well you'd have to get into the legal case for the specifics, but I don't think this is an accurate assumption to make. They can just see the product "on the shelf", test it for themselves, realize it can be used to violate the Clean Air Act, and then request the ability to talk to the consumers of the product to see how they use the product or if they've used it to violate the Clean Air Act. You don't have to engage with a specific person at all.

How else do you get what might be illegal products off the shelves? Perhaps the users primarily use it for other purposes and the interviews bear that out? That would inform the DOJ and the court on the merits of the case.