You *could* subpoena the records directly from Verizon through a court order as a matter of the discovery process.
There are also many private investigators who get those records by paying an insider to give it to them. It happens all the time from what the P.I.'s tell me. There's also a service online that does it, too. It's pretty big business.
THe Feds have cracked down on companies that were slipping in the backdoor and getting private cell records... the company I was using for over 10 years went down in flames along with many others.
Can you still get those things? Yes ...but it is very expensive and you do need to know the right people.
As paranoid as ANS and HKS proclaimed that they were about non-ET media and paparazzi, I always kind of pictured them using lots of disposable cell phones and just throwing them away.
I kinda figured that was what happened when ANS called Virgie after Daniel died and then when Virgie tried to call her back, the number had already been disconnected.