Holding funds to protect the bank and customer

Someone opened an account in a small Louisana bank on June 3, with a bill payment check drawn on Chase bank. We placed a new account hold on it. The hold expired and funds became available but there were no transactions in the account. June 13, we receive two wires in this account from Chase Bank - memo says "for my wife Kelly Laura" and the wire came to our customer's account (not Kelly Laura). When we questioned our customer she stated "it’s for her daughter from the daughters finance that lives in Chicago and it’s for moving expenses." We asked her to come in with her daughter but she says she couldn't because the daughter is not here. We believe our customer is being scammed or something. Multiple attempts to get someone with Chase to help finally happened on June 24 when someone from Chase in our area helped us. They also feel there is something suspicious about their account holder and opened an investigation there. Meanwhile we are holding the money. Chase recalled one of the wires totaling $3,500 and we returned it. As of today were still holding $8,897. How long can we hold this, how long can we investigate, or what other actions should we be taking to protect the bank and the customer?