(CNN) -- The chaotic scene unfolded with flash-bang grenades, rubber bullets and clouds of smoke. Canisters whizzed through the air amid deafening booms.
Marine Lance Cpl. Scott Olsen went down.
"Medic! Medic!" someone yelled.
Olsen, 24, had seen his share of war in two tours of Iraq as a Marine. He was lucky, returning home physically unscathed.
But Tuesday evening, near the corner of 14th Avenue and Broadway in Oakland, California, Olsen went down.
The video images went viral: streams of crimson flowing down Olsen's head, his black T-shirt adorned with a white dove of peace, the war veteran carried to a hospital.
And with that, the Occupy movement had a face.
"We are all Scott Olsen," declared its website.
"It's ironic," said his uncle George Nygaard, that Olsen should be the poster child for this movement.
Ironic, said Olsen's Marine buddy and current roommate Keith Shannon, that a young man who fought for American freedoms should be injured exercising those same freedoms at home.
He was 14 at the time of the September 11 attacks and graduated in 2005 from Onalaska High School with the same sense of patriotism that drove so many young men and women to join the military.
He was working at Lindy's Subs and Salads when he decided to enlist. Soon, he was in Twentynine Palms in the Mojave Desert for training and the next year on his way to war.
Olsen deployed twice with the 3rd Battalion, 4th Marine Regiment to Iraq's Anbar province, site of some the war's fiercest battles.
Shannon said they often encountered makeshift bombs in their 2006 tour during which 15 of their fellow Marines died.
Nygaard said Olsen told him about a couple of close calls, one in which he rolled over a roadside bomb that somehow failed to detonate.
Olsen had always been a quiet, shy kid, Nygaard said. A computer whiz, not a jock. And not the type of young man his friends had expected to become an activist.
But war touched Olsen as it does almost everyone who comes that close.
After his last tour of Iraq, he returned home with serious misgivings and gravitated to Nygaard, a former Marine himself who had returned from Vietnam feeling similarly.
In small-town Wisconsin, uncle and nephew talked to each other about the larger issues of war.
"He came back thinking there were better ways to deal with things than war," Nygaard said.
Olsen's parents, Nygaard said, didn't always understand the change in their son. But Nygaard felt an affinity for the young man.
"I am so much more proud of him now than when he was in (the Marine Corps), because he followed through on his convictions," Nygaard said.
Those convictions led Olsen to Madison this year to join protests of a bill by Gov. Scott Walker to weaken organized labor in Wisconsin.
"Scott thought the workers were getting screwed," said Nygaard, who was on the streets with his nephew.
This summer, Olsen's friend Shannon helped him get a job at OPSWAT, a technology firm in San Francisco.
By then, Olsen had become deeply involved with Veterans for Peace and Iraq Veterans Against the War. At one event, he stood with a poster that read: "32 veterans will try to commit suicide every day and 18 will succeed."
"He worried deeply about his fellow brothers and sisters who are veterans," Nygaard said.
That's what prompted him to join the Occupy movement, first in San Francisco and then across the bay in Oakland, Nygaard said. Olsen knew there were many veterans among America's down and out.
For the past three weeks, he was working during the day and out all night at the Occupy protests, Shannon said. He came home only three or four times to the Daly City apartment the two shared -- mainly to do laundry.
Still, the laid-back Olsen was never a screamer. He felt strongly about economic injustice and wanted to add his voice quietly to the fight.
And so, Tuesday night, he was standing there, almost at parade rest, when he went down, witnesses said.
He suffered a skull fracture and was in fair condition in the intensive care unit at Highland Hospital, a hospital spokesman said.
Shannon and Nygaard said Olsen was conscious and communicating by writing on a notepad. Shannon said he has been told Olsen has asked to see him, but doctors have limited visitors. Olsen's parents were with him at the hospital.
Meanwhile, Oakland police are investigating how Olsen was hurt. Protesters gathered for a vigil in his name.
National outcry over police treatment of the protesters -- many others were injured or sickened by tear gas -- prompted Oakland Mayor Jean Quan to take responsibility for those who were hurt.
And Scott Olsen became a household name.
But back in Chaseburg, Wisconsin, Nygaard worried for his nephew.
Concussions, he said, can come back to haunt you, even after you get over the bruises. A lot of veterans know that from Iraq and Afghanistan, where head injuries have been common. Only Olsen's luck ran out here, in America. Nygaard just hopes his nephew will recover to tell his own story.
CNN's Barbara Starr contributed to this report.