DESERTBOB (not its real name) is a troll.
It regularly frequents at least twenty news groups,
including many rabid/sex/racist groups.
Normally, it starts off with reasonable, even witty lines,
but rapidly drifts into lies, abuse and stupidity.
Check its details at Google Groups at this URL

http://groups.google.com/groups/prof...n7nbF1Te82ZIng

It is a sad creature, deserving of pity, not anger.
Any direct response simply feeds it,
but it will go away if you ignore it.