Story highlights Guantanamo detainee Omar Khadr is transported back to Canada

He pleaded guilty to murder and other charges under a plea deal in 2010

He admitted throwing a grenade that killed a U.S. soldier in 2002

Guantanamo detainee Omar Khadr has been transferred to his homeland of Canada to serve the remainder of his sentence, Canada's Public Safety Minister Vic Toews said Saturday.

Khadr boarded a military plane at the Guantanamo Naval base in Cuba and arrived at a military airbase in Trenton, Ontario. He will serve the rest of his sentence at Millhaven Prison in Bath, Ontario, about 130 miles east of Toronto.

The case and the prisoner's legal fate have sparked controversy among Canadians. Many think his sentence has been too lenient. Others, noting his capture at age 15, think he should have been treated as a child soldier and point to alleged mistreatment while in custody.

Under a plea deal with military prosecutors in October 2010, Khadr admitted to throwing a grenade during a 2002 firefight in Afghanistan that killed Sgt. First Class Christopher Speer, a member a U.S. Army Special Forces Unit.

He pleaded guilty to murder, attempted murder, providing material support for terrorism, spying and conspiracy.

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"This transfer occurs following a process initiated by the United States government and determined in accordance with Canadian law," Toews said.

"I am satisfied the Correctional Service of Canada can administer Omar Khadr's sentence in a manner which recognizes the serious nature of the crimes that he has committed and ensure the safety of Canadians is protected during incarceration," he said, adding that the Canadian government would have no say in parole proceedings.

As part the plea deal, Khadr received an eight-year sentence with no credit for time served. Khadr's lawyers say Khadr agreed to the plea deal under the condition that he would serve most of the sentence in Canada.

Khadr's lawyers say the transfer was delayed for months as the Canadian government seemed to drag its feet.

Earlier this year, U.S. Defense Secretary Leon Panetta told CNN that Khadr's repatriation would mark a significant step forward in eventually closing Guantanamo.

Two senior Obama administration officials said it took about a year to work out arrangements with Canadians for the transfer.

Negotiations were a very long and complicated process, and there were extensive conversations with Canadians, one of the officials said.

There were a lot of legal hurdles on the U.S. side and clearly hesitation on the part of Canadian government to do this because the public is polarized about Khadr, the official said.

Khadr was the only remaining Western detainee at Guantanamo.

His repatriation in Canada is highly controversial, due in large part to the views held by his family members. His father, Ahmed Khadr was a close associate of Osama Bin Laden and openly said he believed it was his Islamic duty to train his children in jihad.

Human rights groups around the world have denounced Khadr's capture at the age of 15 and his 10-year detention at Guantanamo.

"Given the Obama administration's glacial pace towards closing the U.S.-controlled detention center, little and late though it is, today's news represents progress," Amnesty International USA's Executive Director Suzanne Nossel said in a statement.

Canada should conduct a full investigation into Khadr's allegations of torture and "remedy for the human rights violations he suffered," she said.

The Pentagon said that currently 166 detainees remain in detention at Guantanamo Bay.