Br-Bromo-D-fly has an alpha-methyl (amphetamine) and also has aromatic furan rings whereas 2c-b fly has no alpha methyl (phenethylamine) and has saturated (non-aromatic) "wings" (tetrahydrofuran rings). 

This was a really bad mix up.  It is really terrible and it could have been much worse.  Luckily information was made available in a rapid manner via the internet.  This definitely saved lives.