That's the problem with a grand jury. The prosecution doesn't have enough evidence to bring formal charges, so they resort to lies and bullshit without the accused even knowing of these "charges" or have a chance to defend themselves, resulting in an indictment. A clear violation of the 6th. Amendment.
“In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defense.”
How many of those "immigrants" will attend their court cases?