How to verify your vendor (real/scam/re-seller-producer)?

You may get sealed and signed scanned letters from private or government body confirming the reality of the seller, who is capable to provide x commodities, most of procurement and purchased failed to verify such a documents which show reality and worked probably with the well-known419 scammers. It is not easy, but you have to give some trust with those scammers, never send passport copy or company account. Verification takes a little time and you can read the purpose in the return questioners, such as Payment terms in Foreign bank but Deposit in that country (Africa), when you verified the Foreign bank details you will find it is real and exist, available and clear. but the purpose to using this account from scams to show that they have investors and having foreign accounts. but the deposit or tax fees, or booking fees or what so ever will be required to be transfer to local bank by T/T or By Western Union or Money Grams. I believe that you have to stop further correspondences, except you need to know more. this is possible when you show the person that you already discovered him and checked documents by the US embassy or Ministries, and show that you have been advised to report to The inter-pole , but you did not do that as you believe there is some thing behind this person to do this scams... how ever you can discover all the people behind that if you need to arrive to this level, you shall be having and high attention and careful of what they can do. however, you can track them and found them all. but need you to be more than smart