From "Perpetrate" - "To be responsible for; commit; to accomplish; to bring about." (The American Heritage College Dictionary) According to Black's Law Dictionary, the word "perpetrator" denotes the person who actually commits a crime." "But, where a servant of a railroad company is killed through the negligence of a co-worker, the company itself may be regarded as the "perpetrator" of the act, within the meaning of a statute giving an action against the perpetrator."
A person who provokes or commits an act against another, usually in reference to the commission of a crime or violent occurrence. For the purpose of the reporting requirement, perpetrator refers to the person who is the initial aggressor.
A participant in the killing of the Jews. This term includes all those who were involved even from far away: bureaucrats, lawyers, architects, chemists, businessmen, railroad officials, diplomats, etc.