A rally on Thursday demanding justice for whistleblower Bradley Manning was followed by a group of at least sixty protesters showing up at the Obama campaign headquarters in Oakland, California.

According to the Washington Whispers blog at U.S. News, a member of Iraq Veterans Against the War handed a letter to campaign volunteers and demanded that they fax it to the White House. Rainey Reitman, a representative of the Electronic Frontier Foundation who had spoken at the rally, later confirmed that the letter did go out.

"President Obama made a... statement in May 2011: 'In the 21st century, information is power,'" it read. "We now ask that President Obama honor those words by freeing American truth-teller Bradley Manning."

Some of the protesters then attempted to sit down on the floor in the middle of the office, and a noisy scuffle broke out between protesters and volunteers, although it was not clear who had started it. Iraq War veteran Scott Olsen -- who was severely injured by a police projectile last fall during an Occupy Oakland protest -- filmed the scuffle and said it included "pushing, shoving, brandishing of chairs."

Seven protesters then linked arms inside the office and refused to leave. After several hours of negotiations with police officers, one did leave, while the others -- including Olsen -- were arrested for trespassing. The remaining protesters outside the building dispersed peacefully.

This video was uploaded to YouTube by ScottOlsenVet on August 16, 2012.