Agree wholeheartedly that the law should have the right to dig into cell records in such cases but I can only assume that without a witness giving them the right to dig into the records, it is a "privacy" issue which would require changes/challenges to the Charter.  And to be fair would open up a lot of other cans of worms as it would massively open up police authority since electronic privacy falls into the same category as physical and allowing them to dig into cell records without a witness would also allow them to enter your home or search your trunk willy nilly.  Very tricky.