There is no duty to keep a copy of messages and private data on your phone for the FBI to peruse at its leisure. Quite the opposite, actually (according to the constitution).

It is pretty clear to me that law enforcement conspired to abuse a border crossing to effect basically an unconstitutional search ("fishing expedition"), which it would never have gotten a warrant for.

This is them being spiteful after that whole thing failed. Note how law enforcement basically admits this on the record. The whole thing is a disgrace; every decisionmaker involved in this should be sacked immediately.