KEY POINTS:
At first, the anti-globalisation protest seems good-natured, as young people march through sunlit city streets carrying signs denouncing war and capitalism.
But as dusk falls it grows ugly. Police order the crowd to disperse. Angry voices and sirens fill the soundtrack as protesters trash property. The camera zooms
in on a young man wrestled to the ground by police.
This footage, shot in San Francisco in July 2005 by freelance journalist Josh Wolf, later hit the local TV news.
Wolf was a protest veteran with access to the activist community. In February last year a federal grand jury was convened to discover if protesters had tried to set fire to a police car.
This seemed a case of overkill, but the US Justice Department, arguing that the vehicle had been paid for, in part, by federal dollars, claimed jurisdiction.
After tracking Wolf via the footage aired on TV, the grand jury asked for his video out-takes. Wolf refused, arguing he was protected by the First Amendment. But Judge William Alsup thought otherwise, finding Wolf guilty of civil contempt and sentencing him to "coercive custody" until he relented.
On August 1 Wolf, 24, reported to a federal detention centre at Dublin, California. Apart from a brief spell a month later, while the US 9th Circuit Court of Appeals heard and denied his appeal, he has been there ever since.
"Everyone thinks this is a pretext to identify protesters and threaten voices of dissent against the Administration," says Julian Davis, who runs the Josh Wolf Coalition that campaigns for his freedom. "Josh didn't want to be part of a witch-hunt and name names."
Although Wolf is allowed to speak only to his lawyers and close family members, his thoughts - transcribed from long hand - are posted at joshwolf.net. "He's taking a stand on principle," says Davis. "He doesn't want reporters turned into an investigative arm of law enforcement."
Now Wolf has passed a milestone, chalking up a new record for modern US journalists who have spent time banged up for contempt.
Unless he co-operates or the judge relents - both unlikely - he will be jailed until July. If the grand jury is extended he might even languish in the detention centre longer.
Wolf has become a cause celebre on an issue that has riled the US media as more and more reporters are threatened with contempt when they refuse to divulge anonymous sources to grand juries.
The most famous case involved Valerie Plame, the CIA officer whose identity was leaked to journalists in 2003 - a criminal offence.
A grand jury finally charged Vice-President Cheney's top aide Lewis "Scooter" Libby, whose perjury trial is nearing its climax in Washington.
Three high-profile correspondents have testified, including Judith Miller, a former New York Times reporter who spent 85 days in jail for contempt rather than reveal her source, apparently none other than Libby, although Plame's name was first leaked by Deputy Secretary of State Richard Armitage, cleared because he was unaware of her covert status.
Miller agreed to testify after Libby gave his consent. Back in California the Justice Department sentenced San Francisco reporters Mark Fainaru-Wada and Lance Williams to 18 months after they refused to reveal who leaked them testimony during the 2003 Balco scandal, when US athletes were accused of using steroids.
"There's no national security issue here," Williams said. "The only thing on the line is the Government's claim that it has the absolute right to make reporters testify."
The pair, who faced longer jail terms than the convicted dope dealers, were alarmed that the Government seemed intent on "turning reporters into informants".
Ironically, President Bush congratulated the reporters for their work in person.
Last week the Government dropped its contempt charges when Troy Elllerman, a defence attorney in the Balco case, admitted he had leaked testimony. Neither reporter has confirmed that Ellerman was their source.
Elsewhere, the US 2nd Circuit Court of Appeals ruled that New York Times reporter Philip Shenon and Judith Miller must surrender phone records for stories written in 2001 about a Government plan to freeze the assets of two Muslim charities.
The legal framework for the clash between the Justice Department and the Fourth Estate is a 1972 Supreme Court decision, Branzburg v. Hayes. It said reporters who refused to testify could face contempt charges. Federal prosecutors have used this ruling to deny journalists any special privileges under the First Amendment, which protects free speech.
Crucially, the Supreme Court also said courts should observe a "proper balance" between a free press and the legal obligation of citizens to testify in criminal cases. Media and legal groups are almost unanimous in insisting the Bush Administration has gone too far.
