Just to clarify, the sitting grand jury does not then sit on the jury for the trial.

That's generally right. In Fulton County they sit for two months. There were two different grand jurys here, though.

There was a Special Grand Jury who met for 8 months and investigated the specific crimes related to the Trump case. They issued a report in January detailing all of the evidence that they heard.

In GA, though, a Special Grand Jury can't issue an indictment. The report was passed to a normal grand jury who heard all of the evidence, then issued the indictment. That grand jury was first seated on July 11th.

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