If you mean what I think you mean, check the poster's headers ...
    X-Complaints-To: abuse@newsdemon.com

I find it handy to add appropriate rules to my newsreader's "killfile"
so that nuisance messages become invisible.

You seem to be using Google Groups, which sadly doesn't have "killfiles"
or filtering. Unless I'm wrong? However Google Groups does have a
"report abuse" link in the "options" at the top of the offending message.

So yes you can do something. Several things in fact. You probably know
all this already - but you *did* ask :-)

He's spamming other groups too, not just c.l.j.d

It's even more tiresome seeing it twice over :-)

David Harper
Cambridge, England