OTTAWA — Canada's top Mountie says the tough terrain of the southwestern Philippines may make it difficult to find the killers of two Canadian hostages, but it won't prevent the ongoing effort to bring them to justice.
RCMP Commissioner Bob Paulson's commitment was affirmed Monday by Prime Minister Justin Trudeau following the death of Canadian Robert Hall, who had been held hostage by Abu Sayyaf since September 2015.
Hall's death comes after the execution in April of fellow Canadian John Ridsdel, who was snatched from a marina by Abu Sayyaf along with Norwegian Kjartan Sekkingstad and a Philippines national last September.
Paulson said the RCMP is helping local authorities give chase to the kidnappers, "but as you know, it's a very difficult piece of geography and it's a very complex and challenging environment."
The Mounties are conducting an extraterritorial investigation into the murders, meaning the perpetrators could one day face justice in Canada, he added.
Trudeau said Canada holds Abu Sayyaf fully responsible for Hall's death.
"We are more committed than ever to working with the government of the Philippines and international partners to pursue those responsible for these heinous acts and bring them to justice, however long it takes," Trudeau said.
Officials in the Philippines confirmed Tuesday that Hall was beheaded by Abu Sayyaf militants.
Presidential spokesman Herminio Coloma issued a statement condemning Hall's "the brutal and senseless murder."
"This latest heinous crime serves to strengthen our government's resolve to put an end to this reign of terror and banditry," he said.
A militant video obtained by Philippine police officials showed Hall in an orange shirt and kneeling in front of a black Islamic State-style flag before he was killed in a jungle area.
Abu Sayyaf operates mainly in the south of the Philippines, in the western Mindano and the Sulu Archipelago, but staged a major attack in 2004 that killed more than 100 people when militants bombed a ferry in Manila Bay.
In recent years, Philippines security forces have attacked Abu Sayyaf, killing senior leaders and arresting others, but they've been unable to end the group's kidnapping, extortion and terrorist activities.
The Washington-based SITE Intelligence group said the militants released a video that showed Ridsdel, 68, being beheaded. The militants said they were angry the Canadian government had failed to meet their demands for ransom.
In an echo of that tragedy, police in the southern Philippines were investigating the discovery Monday of a severed head, found in a plastic bag on a street in the Sulu province town of Jolo, to determine whether it was related to Hall's murder.
"Our troops thought it was a bomb but found out it was a head," Police Supt. Junpikar Sitin told The Associated Press in a telephone interview from the mainly poor Muslim region.
Trudeau called terrorism "a scourge on the world," and said all of Canada is mourning with Hall's family.
"Too many families have endured the unspeakable grief the Hall family is feeling today because of these senseless acts of hatred," Trudeau said. "On behalf of them and all Canadians, we mourn their loss and reassert our resolve."
Trudeau said Philippines President Benigno Aquino has offered his condolences and regrets over the murder of Hall, whose family the prime minister praised.
"The Hall family has shown great strength of character in their resilience and are admirable in the face of this terrible situation," he said. "This is a grievous loss for them and their country mourns with them."
Hall was born in Calgary, but lived various places in Western Canada, and his career path took him from insurance sales to welding to acting, the Globe and Mail reported after he was taken hostage last September. Hall's stepmother, Catherine Dafoe Hall, declined comment when contacted by The Canadian Press on Monday.
Last month, the militants threatened to kill one of the two surviving western hostages on June 13 if their demands weren't met.
Another video released by the militants last month showed the three remaining hostages pleading for help from the Canadian and Philippines government as gun-wielding hooded captors stood behind them.
Trudeau has steadfastly refused to entertain the thought of paying ransom to hostage takers. In the wake of Ridsdel's execution, he said Canada would never pay a ransom for the hostages in the Philippines, and last month persuaded leaders of the other G7 countries to reiterate their opposition to paying ransoms.
On Monday, he repeated that paying ransoms would put more Canadians in danger.
"Canada cannot and will not pay ransoms to terrorists," he said. "We will not turn the Maple Leaf worn with pride by over three million Canadians abroad into targets."
Interim Conservative Leader Rona Ambrose also expressed shock and outrage at the news of Hall's execution.
"The threat of radical and barbaric acts of terrorism remains very real. Canada is not immune to the danger presented by global terror networks," she said in a statement.
"We must stand in solidarity not just with the victims but with our allies around the world as we work together to disrupt and destroy these terrorist organizations."
— With files from Jim Bronskill and The Associated Press