The article describes some circumstances under which a cell phone can be more precisely located.

> Similarly, if you make an emergency 911 call, your company will use three towers to triangulate your location; if you’re using a smartphone, it will use G.P.S. to pinpoint where you are. If you’re the target of an ongoing investigation and law-enforcement agencies want to track you, they can ask a phone company to “ping” your phone in real time.

The “ping” part caught my attention: this sounds like a method that actively queries the phone in a way that could be detected by the end user. Does anyone know if this is possible to detect? Would, for example, an Android phone allow a developer to write an app that could detect this and notify the user?

Just like the inmate in Texas executed, and (wrongfully?) convicted on pseudo-science arson investigation evidence.

I wonder what other type of crap is putting innocent people in jail? Maybe more interesting question: how can a jury of average citizens be expected to weigh this evidence when even FBI task forces can't completely figure it out?

If all they have is location on a phone, that could also place other people in the area though. But I guess, that's irrelevant. There's also the chance that the murderer didn't carry their cell phone in the area whatsoever. I mean who goes and murders someone and talks on their phone at the same time anyway?

This is why I generally like having features like GPS and Google location tracking turned on. The police, government and large corporations already have access to lousy data they will happily use to my detriment. If I have better data, I can use it to my benefit.

This reads like a textbook example of "circumstantial evidence".

"A GPS transmitter" ... "Seize the GPS chip" an accurate description of technology is always nice