How juries are chosen

Jury selection began this week in the trial of St. Anthony office Jeronimo Yanez, who's charged in the killing of Philando Castile during a traffic stop last July.

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As with any trial, the goal is to make sure the defendant gets a fair shake.

"Our system is based on the idea that when a person is tried, the information they're judged on is solely based on what they hear in the courtroom, not what they hear from the press or from other people, or from previous experiences," said National Jury Project Midwest President Diane Wiley, who works as a consultant during trials.

Here's a look at how it's done.

What's a jury pool?

The term refers to the group of people who have received notices in the mail informing them that they've been selected for jury duty. In Minnesota, jurors are selected at random by computer from a list of people with drivers licenses, state IDs and those who have registered to vote.

When they show up, potential jurors will be told about what's going to happen during the case and how to behave.

In some cases, like the Yanez trial, jurors will be ordered not to discuss any details of the trial with anyone. They also may be ordered not to consume any media or social media about the case or to investigate any details of it online. They're then sworn in and given a questionnaire to fill out.

What's on the juror questionnaire?

In the Yanez case, the questionnaire includes sections about potential jurors' relationships with police or others involved in the trial, the media they consume and what they know about the case. The second-to-last question asks the potential juror's opinion on the "American criminal justice system."

Attorneys on both sides scrutinize the responses.

It's also not unusual for attorneys to investigate public records or publicly available information about the potential juror to try to find things that indicate that they might not be fair during the trial. In the Yanez trial, prosecutors printed out pro-law enforcement Facebook posts made by one prospective juror.

Investigators sometimes even drive past the potential juror's house to look at car bumper stickers.

"It's not done all that often, but when you have a case of this type, it's more likely that it will be done," Wiley said. "They can't do anything illegal. They can't contact the juror. They can't contact anyone who knows the juror. But they can look at public records."

What does jury questioning look like?

After the questionnaire is turned over to attorneys, a potential juror is brought into the courtroom, seated in the witness box, and asked questions by the judge and attorneys from both sides.

If attorneys from either the defense or prosecution believe the potential juror won't be able to fairly consider the evidence in the case, they can ask the judge for a "cause challenge," excusing that person from the pool. Attorneys from the other side can either agree or contest that challenge. The judge decides whether or not to excuse the potential juror.

"The way that the system is set up, you're actually unpicking the jury, rather than picking the jury," Wiley said. "A group of people are brought in. The first thing that's done is you decide whether or not there are some of these people who have opinions that are so strong that they can't be fair, and those people are excused."

How is the final jury selected?

Once a sufficient number of potential jurors make it to the next round, attorneys whittle down the jury by using what's called peremptory challenges, which they can use to strike people from the jury pool without cause. In the Yanez trial, the defense received five strikes; the prosecution has three.

Wiley said there are certain things attorneys will be looking at when they use their strikes.

"Who are the people that we feel would be most likely to be unfair to our client or have opinions that would make it hard to be fair?" Wiley said. "People who had bad experiences with police, I'd look at that. I'd be looking at what they'd read and heard and how they talked about [the case], if that gave any indication of where their biases lay."

Attorneys cannot use their strikes based solely on race. If they do, the other side can object and the judge can ask attorneys to state their "race neutral reason" for striking the juror.

After all the challenges are made, the remaining group, along with some alternates, will be seated as the jury.