... To bring an indictment, prosecutors would have to persuade 12 of the 23 grand jurors to sign onto the decision. If grand jurors turn them down, it is possible for prosecutors to call in a new group, though they would then have to restart the process.
https://www.washingtonpost.com/national-security/justice-dept-authorized-prosecutors-to-charge-andrew-mccabe/2019/09/12/5b0d48ea-d418-11e9-9343-40db57cf6abd_story.html?noredirect=on
Didn’t that Ronnie Earle down in Texas take his case to dozens of grand juries before one of them would indict Tom DeLay?
Evidence is presented only by the prosecution. There is no defense. Jurors only have to reach a "preponderance of the evidence" level of determination, which is far, far less than "beyond a reasonable doubt".
I served on a fed grand jury for a year hearing dozens of cases. Every single one ended in a plurality in agreement to indict. If they present, it's almost a foregone conclusion that there will be an indictment.