вмешательство(в чьи-либо дела: Putin has long railed against NATO expansion into former Warsaw Pact states as a disrespectful encroachment on Moscow.washingtonpost.com)
главный виновник(e.g.: Only years after the bank imploded and the main culprit found a safe haven in a London suburb, both judicial authorities and media in the United Kingdom now seem to be discovering that something is profoundly wrong here)