These people are just scammers themselves. You pay initial fee and send them information. They say you have a good case but want $4k to do block chain analysis. I did some myself using free online analysis tools and I don’t know how they would be able to track down the scammers. There are thousands of transactions related to original transaction. I also used whois another free tool to trace original website. Found out where they are based but no information available. Found out who they are trading under now. Still no information. Have Java script of the scammers fake website. This company claim they are not scammers as we have seen their face. In that case why not invoice after you have got my money back. You have seen my face too and I’m not a scammer. I’m not going to pay more for no result which is 99% chance given the complexity of the crypto world. Very disappointing. I will pass the information I have gathered to local authorities.