Monster Rat caught in sweden

A 15" rat not including tail was caught in a Swedish home last week. It would seem to me that positive identifucation on the species would be worthwhile and if not able to identify at least do some genetic testing on it. Lately I have been seeing some monster rats in pet shops, my first thought is that a pet rat escaped an took up residence in their home, any thoughts on this?

Is Norway jealous?

Another thread on this topic.