Never pay down a deposit in a bank account until you have met the seller, seen signed a purchase agreement.
No serious private advertisers ask for a down payment before you meet.
Receiving an email with an in-scanned ID does not mean that you have identified the sender. You do this on the spot, when you sign a purchase agreement.
Selling a Focus city bike. Restored from a vintage mtb, everything is set up and checked. New handles and cables. The frame is made of high-quality kinesis aluminum tubes, the bike is lightweight.