LONDON  A Spanish court has taken the first steps toward opening a criminal investigation into allegations that six former high-level Bush administration officials violated international law by providing the legal framework to justify the torture of prisoners at Guantánamo Bay, Cuba, an official close to the case said.

The case, against former Attorney General Alberto R. Gonzales and others, was sent to the prosecutor’s office for review by Baltasar Garzón, the crusading investigative judge who ordered the arrest of the former Chilean dictator Augusto Pinochet. The official said that it was “highly probable” that the case would go forward and that it could lead to arrest warrants.

The move represents a step toward ascertaining the legal accountability of top Bush administration officials for allegations of torture and mistreatment of prisoners in the campaign against terrorism. But some American experts said that even if warrants were issued their significance could be more symbolic than practical, and that it was a near certainty that the warrants would not lead to arrests if the officials did not leave the United States.

The complaint under review also names John C. Yoo, the former Justice Department lawyer who wrote secret legal opinions saying the president had the authority to circumvent the Geneva Conventions, and Douglas J. Feith, the former under secretary of defense for policy.