This seems right to me. As well as pretty darn good police work.
Someone's sharing child pornography. The police look up the IP address and discover that it's coming from a router in Apartment 242, and the police obtain a search warrant for that address.
Except that when they execute the warrant, they discover that there's not child porn on the computer there. So where's the child porn coming from? They download the access data from the router in that apartment and discover that someone else's computer has been access this router -- notwithstanding the fact that the router is password-protected. Surprise!
Which is a pretty good move by the child pornographer at issue. You're worried that the police might figure out it's you if you use peer-to-peer sharing over your own internet connection. So you use the connection of someone else. Someone innocent to cover your tracks.
So the police are stymied, but not for long. They subsequently start using an open-source software program that's aptly named "Moocherhunter" to find out who's been using the router in Apartment 242. They use a directional antenna and find out that the signal of the computer that's accessing the router in Apartment 242 is much stronger when it's pointed at . . . Apartment 243.
So the police then obtain a search warrant for Apartment 243. And, lo and behold, they find two computers there that have indeed accessed the router in Apartment 242 and that contain kiddie porn.
Hence the arrest and conviction.
The defendant appeals, saying that the "search" using the Moocherhunter software violated the Fourth Amendment. But the Ninth Circuit disagrees. Which seems right. If you're pumping out electronic transmissions from your computer to pimp your neighbor's password-protected internet connection without his consent, it's not impermissible for the police (or anyone else) to investigate where those transmissions are coming from. You shouldn't be grabbing their internet in the first place, and your transmissions are in any event public and it's okay for someone else (including but not limited to the police) to point software in your direction to figure out where those transmissions are coming from.
Makes sense to me. As well as to Judge Rawlinson and the rest of the panel.
