OAKLAND, Calif. — The Iraq War veteran injured during a clash between police and anti-Wall Street protesters wasn’t taking part in the demonstrations out of economic want.

Scott Olsen, 24, makes a good living at a software company and rents a hillside apartment with views of San Francisco Bay. And yet, his friends say, he felt so strongly about economic inequality in the country that he fought for that he slept at a San Francisco protest camp after work.

“He felt you shouldn’t wait until something is affecting you to get out and do something about it,” said friend and roommate Keith Shannon, who served with Olsen in Iraq.

It was that feeling that drew him to Oakland on Tuesday night, when the clashes broke out and Olsen was struck by a projectile that fractured his skull. Police say they responded only when protesters began throwing bottles and other items at them.

Now, even as officials investigate exactly where the projectile came from, and from whom, Olsen has become a rallying cry for the Occupy Wall Street demonstrators across the nation, with Twitter users and protest websites declaring: “We are all Scott Olsen.”

The group Iraq Veterans Against the War blamed police. Police say they used tear gas and bean bag rounds, not flash grenades and rubber bullets as some demonstrators have charged.

Interim Oakland police Chief Howard Jordan said Wednesday that the charges of excessive use of force are being investigated. He did not return repeated calls seeking comment on Thursday.

Olsen’s condition improved on Thursday, with doctors transferring him from the emergency room to an intensive care unit. Shannon said Olsen is scheduled for surgery to relieve pressure from brain swelling. His parents were flying to Oakland from Wisconsin, his uncle said.

Joshua Shepherd, 27, a Navy veteran who was standing nearby when Olsen got struck, said he didn’t know what hit him. “It was like a war zone,” he said.

Shepherd said it’s a cruel irony that Olsen is fighting for his life in the country that he fought to protect. “He was over there protecting the rights and freedoms of America and he comes home, exercises his “freedoms” and, it’s here, where he’s nearly fatally wounded,” Shepherd said.

Olsen was awarded seven medals while serving in the U.S. Marine Corps, which he left as a lance corporal in November 2009 after serving for four years. One of them was the Navy-Marine Corps Achievement Medal.