District of Columbia Local Prosecutor Establishment Act of 2017 This bill amends the District of Columbia Code to shift the responsibility for conducting prosecutions for violations of Washington, DC laws from the Corporation Counsel for the District of Columbia (Attorney General for the District) or his or her assistants to the head of the office designated under DC local law as the one responsible for conducting such prosecutions (local prosecutor's office) or his or her assistants. An indictment or information brought in the name of: the United States in the U.S. District Court for the District of Columbia may include charges of offenses prosecutable by DC if the head of the local prosecutor's office consents to such inclusion in writing, and DC in the Superior Court of the District of Columbia may be joined for trial in the U.S. District Court for the District of Columbia with an indictment or information brought in that court if the offenses charged could have been joined in the same indictment or information and if the head of the local prosecutor's office consents to such joinder. Nothing in this Act shall affect the authority of the Attorney General or the U.S. Attorney for the District of Columbia to exercise jurisdiction concerning violations of federal laws.