...how come it took authorities so long to track this guy down.
Edit: oops, Aardwolfe beat me to it while I was typing out my treatise...
He was using a T-mobile phone with an expired calling plan. I don't know if it was originally his phone or someone else's. Anyway, so this phone doesn't have its own phone number, so the 911 operators wouldn't say, "Ah, look, it's xxx-xxx-xxxx calling again." And since it's not on a calling plan, there's no address associated with it. So, when he calls 911 and doesn't speak, but makes weird noises, the protocols that the operators use require them to spend time listening and trying to assess the situation.
I remember back when cell phones were first getting really popular, there would be many thousands of accidental calls to 911 because on many Nokias or Motorolas (I forget which) if the #9 key is held down, it would speed dial 911 in your pocket or purse. In California, where the CHP took all cell calls to 911 back then (and still do, in most areas), because of their protocol, the operators would need to sit there with each and every accidentally dialed call and try and figure out if it was a misdial or someone really in trouble, but who couldn't speak. I remember that my non-flip Nokia would allow 911 to be dialed even with the keypad "lock" feature turned on--in case someone unfamiliar with your phone needed to call 911. I once pulled it out of my pocket with "915" on the screen, so that was a close call (ugh, no pun intended)
So, basically all you can do is wait till he calls, track down the cell tower, and then send (in this case, an FCC crew) out to that area while he is on the phone and track down his signal. Alas, it's not like on the TV show
24 where you can triangulate a cell call from a computer in about 30 seconds and then send Jack Bauer to retrieve the guy's phone.