To pawn somebody else's belongings without their permission *is* in fact theft. It does not matter that you and your ex-husband are divorced; if you participated in taking his parent's belongings, you could be sued for their value. You would not be liable for the value of any of your ex-husband's belongings, inasmuch as he had the right to pawn them or give them to you to pawn on his behalf. (Though the family may now be claiming either that 1) those items belonged to the parents, not the son; or that 2) you took his items without his  permission--this would present possible factual issues, though legally, if the items were his and he gave them to you to pawn, you are not legally liable.)There is no requirement that someone whose items were taken without permission must file a police report or press charges. That person may elect to simply sue and try to collect the items' value.