The Washington Post reported that the main issue was over the wooden building protesters erected. No permit was ever filed, rendering the structure illegal.
Unlike other incidents in Oakland, Calif., and New York, police in D.C. have rarely clashed with members of the Occupy movement. But after protesters ignored warnings that they had an hour to dismantle the structure, police moved in to tear it down themselves.
Prior to the arrests, police barricaded the structure and a building inspector from the National Park Service analyzed it. After, the inspector deemed the building dangerous, and posted numerous orange signs that read "Danger."
While some protesters moved away from the building, the others who stayed were removed and handcuffed.
The structure was built overnight in McPherson Square as a place where protesters could stay warm in the winter and hold their daily general assembly meetings, according to Wade Simmons, one of the Occupy demonstrators.
... About a dozen people remained perched on top of or inside the building, which was donated by a father-son architect team. As many as 200 people gathered at the park to watch the standoff.
For the most part, the incident was not violent. According to The Washington Post, at around 6 p.m. police arrested at least eight protesters who were inside the building's base and were working on the six people who placed themselves atop the roof.