While the jury in the Yanez case deliberates, a look at how juries work

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Jurors in the trial of St. Anthony police officer Jeronimo Yanez have been deliberating in the case since Monday.

The judge's instructions to the jury before they began their work emphasized the gravity of their role: "The responsibility that rests upon you should be borne courageously and without fear or favor. Be fair and act honestly. Deliberate without prejudice, bias or sympathy and without regard to your own personal likes or dislikes."

As they work toward a verdict, here's a guide to what happens behind the closed doors of a jury room.

How many people are on a jury?

A total of 12 jurors and as many as 6 alternates are chosen from a pool of 50 people. 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.

The alternates hear the case along with the rest of the jury and are available to replace any juror who is excused. Three alternates were selected to hear the Yanez trial, but were excused when the jury went into deliberations.

What is the jury asked to do?

Jurors are asked to return a guilty or not-guilty verdict on each charge brought against the defendant based on the evidence presented during the trial.

"The jury is told to follow the law and apply the law to the facts," said Bradford Colbert, a professor at Mitchell Hamline School of Law.

In his instructions to jurors in the Yanez trial, Judge William Leary explained that the defendant should be presumed innocent until proven guilty, adding, "This presumption remains with the defendant unless and until the defendant has been proven guilty beyond a reasonable doubt." The defendant does not have to prove his or her innocence.

It's up to the state — represented by the prosecution — to prove guilt beyond a reasonable doubt.

The instructions define "reasonable doubt" as "such proof that an ordinary prudent man and woman would would act upon in their daily affairs."

Does the jury have to agree unanimously?

Yes.

It doesn't matter if the jury is split down the middle, or if 11 out of the 12 jurors agree, Colbert said. If even one juror is not in agreement on a verdict, it's a hung jury.

Can a jury reach different verdicts on different charges?

Yes.

A defendant facing multiple charges can be found not guilty on one or more of the charges and guilty on others, for example. A jury can also be hung on one or more of the charges, but reach a verdict on the others.

The judge instructed jurors to consider each of the charges separately: "That you may find the defendant guilty or not guilty as to one of the charged offenses should not control your verdict as to any other offense."

In this case, Yanez faces one count of second-degree manslaughter and two counts of felony dangerous discharge of a firearm.

Is the jury allowed to take notes?

Jurors were allowed to take notes during the trial, and they're allowed to bring those notes with them into deliberations.

But the judge's instructions emphasize that those notes are strictly to be used as a way for jurors to remember things, and "not a substitute for it."

Do jurors have access to evidence as they deliberate?

It depends on the evidence. According to Colbert, the judge and lawyers from each side of the case discuss which evidence should be available to jurors during deliberation. Jurors can also request to see evidence, which the judge can grant at his discretion.

"One of the concerns is, they don't want to emphasize a certain piece of evidence over the other," he said. "[It's up] to the judge's discretion."

Jurors in the Yanez trial requested to see several pieces of evidence again, including the dashcam video from Jeronimo Yanez's squad car that captured the traffic stop when he pulled over Philando Castile.

Judge William Leary allowed the jury to watch the video, but would not allow jurors to bring the transcript of it to the jury room as part of deliberations.

What is the role of the foreperson?

When the jury is first sent into deliberations, its members must choose a foreperson among them to lead the process. The foreperson's opinions in deliberations don't carry any more weight than those of the other jurors.

It's up to that person to lead conversation and to date and sign handwritten requests to the judge. When the jury in the Yanez trial wanted access to individual pieces of evidence, the request came in the form of a handwritten note signed and dated by the jury's foreperson.

The foreperson must also date and sign the verdict form, when the jury has reached its verdict.

What if jurors can't unanimously decide on a verdict?

If jurors are unable to unanimously reach a verdict, the judge can either declare a mistrial, or tell the jury to keep deliberating.

On Wednesday, when the jury in the Yanez trial indicated that they hadn't been able to reach a unanimous verdict, Judge Leary sent them back into deliberations.

There is no set limit on how many times a judge can send a jury that's been unable to reach a unanimous decision back into deliberations, Colbert said.

"But the judge has to be very careful," he said. "Because the law is very clear. A hung jury is a result. So the judge can't say, 'You have to go back and deliberate and come to a verdict.'"

Eventually, he added, forcing a jury back into deliberations over and over again could qualify as jury coercion. The jury doesn't have to reach a verdict if they're unable to agree unanimously.

If, after extended deliberations, a jury cannot reach a unanimous verdict, it's up to the judge's discretion to declare a mistrial.

If the jury is unable to reach a verdict and the judge declares a mistrial, what happens next?

If such a thing were to happen, Ramsey County Attorney John Choi would have to decide if it's worth re-trying the charges that led to the hung jury.

Nationally, only about 25 percent of mistrials are retried, Colbert said.

Two recent cases of charges against police officers ended in hung juries. The trial of former North Charleston police officer Michael Slager, charged with murder in the 2015 shooting death of Walter Scott, was one of them. Slager pleaded guilty to federal civil rights charges last month in a deal that allowed him to avoid retrial of the state's murder charges.

Former University of Cincinnati police officer Ray Tensing's first trial also ended in a hung jury. He is now back on trial for the shooting death of unarmed driver Samuel DuBose during a 2015 traffic stop.