The phone isnt what saves them. They are all automatically saved on the phone companies server. The user cant delete that copy even if they want to. This whole thing is a smoke screen. These texts must be very, very damning.
Dollars to donuts says the FBI will either threaten the phone companies to make them delete the records or the leFtBI will hack into the phone company database and delete the records. Being inept, theyll get caught and explain it as another glitch .
Id they did so this then immediately comes under the RICO statutes as well as others. There are also some Sarbanes/Oxley standards that come into play. I know some may say they are only for banking but that is not true and the Government is not immune