NEW YORK — Sophisticated cyber-scammers are ripping off hundreds of online auction buyers and sellers through bogus escrow services in the latest variation of Internet fraud. Buyers of expensive cameras, computers and cars, including one man who paid $50,000 for what he thought was a new BMW sport-utility vehicle, have been taken in the auction hustle, which emerged on the Internet last fall. Similarly, sellers of expensive jewelry and other items, including a man who sold a used Rolex Presidential watch for $14,000, also have been victimized. The polish on the scam includes elaborate Web sites with names like Premier-escrow.com,...