OTTAWA  The Supreme Court of Canada ruled Friday that Canadian agents violated the rights of the only Canadian citizen held at the Guantánamo Bay detention center when they interrogated him there. But the ruling, the second concerning the man’s politically sensitive case, does not order the government to demand his return to Canada, as he has long requested.

The man, Omar Khadr, was 15 years old and severely wounded when he was captured by American forces in Afghanistan during 2002. Mr. Khadr still faces an American military commission on charges that he killed a member of the United States military with a hand grenade during a battle.

As was the case with its earlier judgment, the Supreme Court was very critical of methods used at Guantánamo both by the United States and visiting Canadian officials. It said that use of tactics like sleep deprivation before Mr. Khadr was questioned by Canadians in 2003 and 2004 were a particularly offensive violation of Canada’s Charter of Rights and Freedoms because of his age.

“Interrogation of a youth, to elicit statements about the most serious criminal charges while detained in these conditions and without access to counsel, and while knowing that the fruits of the interrogations would be shared with the U.S. prosecutors, offends the most basic Canadian standards about the treatment of detained youth suspects,” the court said in its decision.