Falling for fraudsters

Hello, my parents have gone to a “Danish” fraudster on the Laim. He stated (in English) by email that he wanted to sell his vehicle. My parents became aware of him or his vehicle via the Internet. After they had exchanged some mails, they arranged for yesterday morning at a Bielefeld hotel, where the car purchase was to be carried out. The presumed buyer said to be a 65-year-old man who wanted to meet in a Bielefeld hotel. In order to be able to meet half way, he asked my parents to deposit an amount of 3,500 euros at the Postbank. My parents inquired at a bank near them and they were assured that this drive was possible without any problems, since the money in Bielefeld was only possible by my father showing his identity card and the indication of a PIN number. On this statement, my parents asked me to send a letter to the Postbank. The potential seller asked my parents to fax him a copy of the deposit so that he could be sure that my parents would also come to Bielefeld and that he would not have travelled the way out of Denmark for free. ALs my parents then arrived in BIelefeld yesterday and asked at the hotel for the buyer, they had already there to know that about 30 more people had already been there and that with these My parents then went directly to the post office where they had deposited the money and had to find out that the money had already been collected by a third person on Friday. The bank could not give my parents any further statements regarding the pick-up location, time etc.. My parents then drove to the police and filed charges for fraud. Unfortunately, it turned out there that on the certificate, the e my parents have sent the “buyer”, the PIN number, with which the card was collected. The fraudster then forged an identity card and picked up the card. Did someone here experience a similar case and know if my parents have a way to get their money back? Is there a mistake of the bank? I would be very pleased about answers. Thank you in advance Nina