The Supreme Court of Canada has paved the way for the extradition of a Canadian man to the U.S. where he is accused in a decades-old slaying of an aboriginal activist.

John Graham's appeal of lower court rulings was dismissed by the top court on Thursday.

U.S. officials allege that Graham, a former Yukoner who now lives in Vancouver, and another man killed Anna Mae Pictou-Aquash in South Dakota.

Pictou-Aquash, a 30-year-old Mi'kmaq from Nova Scotia, and the two men were all members of the activist group American Indian Movement (AIM).

The group seized control of the village of Wounded Knee in 1973 and two years later the situation escalated into a violent confrontation with the FBI that led to the death of two agents.

Pictou-Aquash's body was found in 1976 with a bullet in her skull that a pathologist said indicated she was killed execution style.

Authorities alleged the AIM group ordered her killing on suspicions she was actually an FBI informant.

In 2005, Arlo Looking Cloud was convicted of first-degree murder in her death and sentenced to life in prison.

He told FBI agents in a videotaped statement shown in court that he saw Graham kill Pictou-Aquash, but later recanted saying he had been plied with alcohol and drugs.

Graham has maintained his innocence.

Graham's lawyers have argued that evidence against him is feeble. Lower courts agreed there were deficiencies in the record of the case provided by U.S. authorities, but said there was enough evidence to justify extradition.

In June 2006, he was ordered to be extradited, but that was stayed pending appeals.

As is usual for leave-to-appeal applications, the Supreme Court gave no reasons for its decision.

With files from the Canadian Press