SAN FRANCISCO, Aug. 1  A freelance journalist and blogger was jailed on Tuesday after refusing to turn over video he took at an anticapitalist protest here last summer and after refusing to testify before a grand jury looking into accusations that crimes were committed at the protest.

The freelancer, Josh Wolf, 24, was taken into custody just before noon after a hearing in front of Judge William Alsup of Federal District Court. Found in contempt, Mr. Wolf was later moved to a federal prison in Dublin, Calif., and could be imprisoned until next summer, when the grand jury term expires, said his lawyer, Jose Luis Fuentes.

Earlier this year, federal prosecutors subpoenaed Mr. Wolf to testify before a grand jury and turn over video from the demonstration, held in the Mission District on July 8, 2005. The protest, tied to a Group of 8 meeting of world economic leaders in Scotland, ended in a clash between demonstrators and the San Francisco police, with one officer sustaining a fractured skull.

A smoke bomb or a firework was also put under a police car, and investigators are looking into whether arson was attempted on a government-financed vehicle.