I'm going to be complaining to Flickr about him, and if we band together we can probably get all the images taken down, and the user banned. He's stolen the work of several artists on dA that I can see, including myself, you, =Eisblume, ~faerieswithoutwax, ~ma-dame, ~DigitalLithium, and more.
Anyway... sorry to be the bearer of bad news, but I thought you'd want to know.
I think complaining to the guy himself isn't going to work. Another deviant did that about six months ago, and never got a reply. Best thing to do is probably send Yahoo (who owns Flickr) an email. Details of that are here: [link]
I emailed them yesterday, and I did mention the other stolen images in my mail. I can't complain on your behalf, though, since I don't own the copyright - you do! So it's probably best if you email them too...
This guy's a repeat offender, I reckon we can get him banned!