When police analyze photographs trying to find where they were taken, they can take the smallest visual clue and turn it into a precise location. If you take a picture of your ten kilos of coke on a certain set of sheets in your bedroom, don't be surprised when FBI specialists determine who made the sheets, the stores they were sold at and the addresses of 100 people who bought them, and then they identify the make of the camera due to lens artifacts and gather a list of people who bought such camera and then do an intersection attack on the list of sheet buyers and camera buyers looking for a unique suspect to pop out. You can say oh they watch every store that sells this like it is humorous but would you also say oh they find every store that sells these sheets? I can go capture all IP addresses downloading this torrent right now, torrents make IP addresses getting them public knowledge, and I am sure that if I do this I will gather tons of IP addresses of people on SR who are getting it, and then it is just a matter of using that intelligence to gather some evidence.