perpetrator
noun [ C ] uk/ˈpɜː.pə.treɪ.tər/ us/ˈpɝː.pə.treɪ.t̬ɚ/ (US informal perp)
犯罪者；行凶者；作恶者
someone who has committed a crime or a violent or harmful act
The perpetrators of the massacre must be brought to justice as war criminals. 大屠杀的参与者必须作为战犯绳之以法。