copy of driver's license req'd to sell to dealer?

[jamese]

The rifle was shipped without a bill of sale or copy of sellers DL. When contacted, the seller refused to send his ID. The shops owner had no choice but to call the ATFE to pick up what was now a contraband rifle and the buyer was out nearly $1000.

MR,
If an FFL-03 or 01 dealer sends a gun to another dealer (transfer) and is done w/o a bill of sale, how does it become a contraband.

Maybe I'm missing something here

Jim