I'm not sure an IMSI catcher would be needed. Cellphone companies CAN triangulate his location for E911 purposes with reasonable accuracy. All LEO would need is to put the apartment block under surveillance for a few days and figure out which resident is home when the laptop connects to the network. This is even easier if he moved around with his laptop.

Wouldn't this take a warrant?

Sounds like IMSI catchers are being used without warrants.

Yes. You would need a warrant for that. I meant in this case they could have easily obtained one. The had the IP, which is how they got IMSI.

I imagine you'd use Stingrays when you want to cast a broad net, i.e. who are the persons who are within X distance of the tracker and were also around at a previous location.

So I can't imagine why they would have wanted to use the Stingray here.

You only need the warrant if you want to use the information you obtained in court. If you just want to figure out how to nail somebody... which is often the hardest part... you just quietly listen in and figure out what things you should be getting warrants for.

>You only need the warrant if you want to use the information you obtained in court. If you just want to figure out how to nail somebody... which is often the hardest part... you just quietly listen in and figure out what things you should be getting warrants for.

That still sounds illegal. "Fruit of a poisonous tree" and all that:

Fruit of the poisonous tree is a legal metaphor in the United States used to describe evidence that is obtained illegally. The logic of the terminology is that if the source (the "tree") of the evidence or evidence itself is tainted, then anything gained (the "fruit") from it is tainted as well.

Yes, and this has been side stepped around for decades.

You find another way of entering evidence that doesn't mention any illegal surveillance. Since you've been watching, you know where it is. Construct a situation in which it is found legally.

See the Snowden revelations and what the DEA has to say about how it does investigations.

Yes, but look up "parallel construction" for numerous examples of law enforcement doing this and working around the "poisonous tree" stuff.

Surveillance doesn't necessarily require a warrant, if it's something like watching who's coming and going from a public vantage point. Wiretapping, reading mail, other eavesdropping would.

Triangulation seems very targeted and would require a warrant (which was the point of my comment).

Right but in this case I imagine they would have gotten a warrant that would give them the IMSI based on the IP in the first place.