Paraphrasing a few statements in the paywalled article:
The Murads are giving the Japan police time to search and investigate before they consider what they should do next. Authorities are searching the river upstream and downstream from where items were found.
Pattie’s husband says despite the latest recovery of her backpack, still don’t have the answer to: did she go on the wrong trail and got lost or fell, or was she abducted and killed.
He asked the police about the tears in the backpack, about what they thought how it came to be in that condition: Knife—animal—water—typhoon that passed through since the time the family had been there searching? Police said damage appeared to be from the stream.