Both things can be true: Karen is responsible for John's death AND law enforcement is trying to cover up their texts/personal convos to spare themselves embarrassment. And let's face it--most of us wouldn't want our personal texts put on blast either, so I can certainly understand their motivations. That they got rid of their phones just prior to the deadline to hold them isn't that big a deal. If they were worried about incriminating themselves, they would have gotten rid of their phones long before the deadline.
Both things can be true: Karen is responsible for John's death AND law enforcement is trying to cover up their texts/personal convos to spare themselves embarrassment. And let's face it--most of us wouldn't want our personal texts put on blast either, so I can certainly understand their motivations. That they got rid of their phones just prior to the deadline to hold them isn't that big a deal. If they were worried about incriminating themselves, they would have gotten rid of their phones long before the deadline.