CHICAGO (CBS)–Day 1 of jury selection for the murder trial of police officer Jason Van Dyke began Wednesday, with hundreds of protestors gathering outside to advocate for his conviction.

Jurors brought into the Leighton Criminal Courthouse could not avoid the throngs of demonstrators who had assembled outside. They voiced phrases like “Can we get justice for LaQuan McDonald? Yes!”

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Organizers say jurors should pay attention to evidence during the trial and consider how the ‘public’ thinks about the killing of 17-year old-Laquan McDonald.

Van Dyke is the first Chicago police officer in decades to be charged with first-degree murder for an on-duty shooting. He shot McDonald 16 times on the night of Oct. 20, 2014, as police were responding to reports the teen was slashing tires near 41st and Pulaski.

McDonald was armed with a knife and allegedly had slashed the tire of a police car before Van Dyke arrived on the scene.

In a report he filed after the shooting, McDonald attacked Van Dyke, and swung the knife in an “aggressive manner.”

However, dashboard camera video released the day Van Dyke was charged with murder contradicts the police account, and shows McDonald walking away from Van Dyke when he was shot.

The trial is anticipated to be one of the most watched trials in America.

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“They should be very much aware of the public sentiment on this case and used that to help inform their decisions as to what justice to look like like,” said demonstrator Amara Enyia, who stood among the sea of protestors on Wednesday.

In his courtroom, Judge Vincent Gaughan told potential jurors to only consider evidence presented in court. But could the worldwide coverage of the shooting and demonstrations outside the court house affect the jurors’ judgment?

CBS legal analyst Irv Miller said the heavy public attention could have an impact on the trial.

“It may discourage some of these people from wanting to sit on the jury,” Miller said.

Two-hundred potential jurors were in court today. Judge Vincent Gaughan read the charges against Van Dyke before sending them to fill out questionnaires.

“Miller said the potential jurors were likely asked questions about their personal lives, beliefs, what magazines they read, what television shows they watch, whether or not they own a gun, whether or not they’re members of the NRA, etc.

“All to get into their heads to see if there’s a bias there that could hurt one side or the other,” Miller said.

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It could take days to select a jury. And until the jury is sworn in, Jason Van Dyke can still ask for a bench trial.