I hope you're able to get to the bottom of this one, Tomas, I see this user has been entering (and winning) a few contests.
I couldn't be more supportive of the drive to reduce plagiarism, but as someone who was accused of plagiarism by a well-intentioned user shortly after joining Steem, and flagged before having a chance to prove myself, I just want to urge anyone who suspects plagiarism to do what Tomas is doing here and practice due diligence to confirm, from outside sources if necessary, the truth of the matter before flagging a user, because it is and should be a devastating allegation.