Comment by dcrazy

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.