Property purchase scam

A guy calls saying he is a foreigner and is interested in buying my property. He asks for my lawyer's number to contact him, sends the passport and other documents to my lawyer, says he will make a purchase and sale document for the property, will first give an amount and then the rest. The day before the appointment to see the property, he says he is having problems making the transfer and needs me to approve the sending of a Swift code from Bank of America. He says he will put me on a call with the bank staff, but I hang up immediately.