Saturday marked two weeks since unarmed Missouri teen Michael Brown was shot and killed by police officer Darren Wilson.

MICHAEL BROWN'S FATHER VIA KSHB: "We're hurt. There's no telling what he's doing. He has his life, but our son is gone."

And many protesters say demonstrations won't end until Officer Wilson is arrested.

In the past couple of days, the streets of Ferguson have been quieting down — but citizens' demands haven't changed. NBC talked to Harvard Law School Professor Charles Ogletree, who had this to say:

"I think the first thing that needs to happen, you need to arrest Officer Wilson. He shot and killed a man, shot him multiple times. ... No one knows anything about him, no one knows why he did it."

So why hasn't Darren Wilson been arrested? As The Christian Science Monitor points out, the belief Wilson should be taken into custody is not one shared by everyone. The outlet reports that divide can even been seen among law professors within the same university.

The Monitor quotes another Harvard law professor who says, "We should not arrest [Officer Darren Wilson] until there's a substantial level of proof of criminality, even if it appeared that the police acted improperly."

But opinions aside, there are also some practical obstacles to moving ahead with any prosecution of Wilson.

FOX NEWS: "With this process, it takes a long time, especially a murder trial. There are so many witnesses. ... And we don't know what those witnesses have to say."

But it's not just time — it's law. This is Missouri's Defense of Justification statute. It gives police officers broad authority to use deadly force in cases when "He or she reasonably believes that such deadly force is necessary to protect himself, when he reasonably believes that such use of deadly force is immediately necessary to effect the arrest" and when the subject "May otherwise endanger life or inflict serious physical injury unless arrested without delay."

It's the same law that was invoked in 2000 after two unarmed men were shot and killed by police at a Berkeley, Missouri, Jack in the Box.

At the time, Ferguson's police chief, Tom Jackson, was deputy commander in Berkeley.

During that investigation, Jackson defended his officers, who claimed the men in the car had started toward the police vehicle in an effort to escape and the officers feared for their lives.

But ​according to The Daily Beast"Investigators decided that the car occupied by the two men had not in fact begun to move in their direction when the fatal shots were fired. The officers insisted they were in fear for their lives nonetheless, essentially arguing that the car was itself a deadly weapon pointed their way. That was enough for the shooting to be ruled justified under Missouri state law."

Business Insider points out, "If Ferguson police officer Darren Wilson is charged in Brown's death, attorneys could invoke this law to argue that he justifiably believed Brown could have endangered his life."

Wilson's supporters also play a large role — pointing to witness accounts that Brown was the aggressor in the situation. And the police union says it's just too soon for judgment when there's no clear picture of what actually happened Aug. 9.

ABC: "He has been vilified by the media and by the politicians."

"A source close to Wilson told ABC News that before the shooting the officer suffered 'a serious facial injury.'"

Wilson's supporters have also started fundraising campaigns for the officer, including aGoFundMe page that has raised more than $230,000. And two Facebook pages in support of Wilson have almost 100,000 likes combined. 

The jury in this case began hearing evidence earlier in the week, but as CNN notes, the process is far from over.

This video includes images from Getty Images.