The killers of British Red Cross worker Khalil Dale threatened to release a video of his execution because their demands for a ransom were not met, it has been reported.
Dale's body was discovered in an apple orchard in the Pakistani city of Quetta, in the Baluchistan province, on Sunday morning, more than four months after he had been taken from a car at gunpoint, 200 metres away from a residence of the International Committee of the Red Cross.
Police in the region said that his mutilated body was found decapitated in a plastic bag with a note claiming that he had been executed because his killers' demands for a ransom had not been fulfilled.
According to media reports in Pakistan, the note added: "We will release video of this killing as the organisation did not fulfil our demands despite repeated warning."
Motives for the death, or the identities of the culprits, remain unclear, although some reports have pointed the finger at the Pakistani Taliban, or the Tehreek-e-Taliban.
Today, a spokesman for the ICRC told Channel 4 News: "We are talking to the Pakistani media, asking them to be mindful of the distress of his family in their use of photos or videos."
Dale's death has sparked international revulsion and condemnation, although the identities of the culprits or motives remain unclear. Britain's foreign secretary, William Hague, said that "tireless efforts" had already been made over the past months to secure the release of the 60-year-old, who had already survived numerous brushes with death while working in Afghanistan, Iraq and Somalia.
This was a shocking and merciless act, carried out by people with no respect for human life and the rule of law. Prime Minister David Cameron
The Pakistani government has expressed its shock and outrage, while Britain's prime minister, David Cameron, added: "This was a shocking and merciless act, carried out by people with no respect for human life and the rule of law. Khalil Dale has dedicated many years of his life to helping some of the most vulnerable people in the world."
Mr Dale had worked for the ICRC and the British Red Cross for many years, and was awarded an MBE for his humanitarian work overseas. He was travelling home from a local school, in a clearly marked ICRC vehicle, when he was ambushed by his kidnappers, and bundled into a car at around 1pm local time.
Police in Pakistan have claimed that the captors demanded a ransom of $30m for his release. The ICRC has said that it had not paid any money, but declined to give details of whether the prospect of paying up had been discussed with the abductors for fear of "giving succour" to other would-be kidnappers.
Numerous theories as to the killers' identities have surfaced. While reports in Pakistan have suggested that the Tehreek-e-Taliban, the Pakistan wing of the Taliban, are behind the killing, the group is understood not to have claimed responsibility as yet.
Others have pointed to the widespread violence meted out by separatist groups in Baluchistan, bordering Afghanistan, which render the region off-limits to many foreign aid workers.
But it has also been suggested that Quetta, Baluchistan's largest city, is a victim to widespread violent crime, including abduction and murder. While some criminal gangs are linked with Islamic militant groups, such as the Afghan or Pakistan Taliban, many others operate on their own terms, or based on other, tribal allegiances in the region.
The ICRC is continuing to work with authorities in Pakistan to try and have the body of Mr Dale, a Yemen-born Scot, repatriated, and to attempt to catch his killers. It has described the death as "senseless and barbaric".
Najum Ul-Saqib Iqbal, a spokesman for the ICRC in Pakistan, said: "Our main focus is on getting the body back to the UK as soon as possible. We are in a period of mourning.
"We are also in contact with the government agencies and law enforcement, who are looking into the matter, and we demand that the government of Pakistan investigate it and find the culprits and discover the reasons behind the killing."
Professor Anatol Lievin, author of Pakistan: A Hard Country, who teaches at Kings College London, said that kidnappings had been taking place in Baluchistan for some time, but that kiling westerners is rare.
"In the past, Quetta's Taliban have not carried out attacks on westerners there," he said. "Pakistan's intelligence have also taken considerable care to ensure westerners don't travel much in the region. There are bandit groups, but in the past, they were careful not to kill westerners, although this could be bungled on their part."
Friends in Dumfries have paid tribute to Mr Dale, who had changed his name from Ken to Khalil when he converted to Islam. He was engaged to be married and had been living in Pakistan for a year.
He was the third westerner to have been kidnapped and beheaded in Pakistan since January 2002, when US journalist Daniel Pearl was murdered in Karachi.
Polish geologist Piotr Stanczak was seized in the town of Attock, 45 miles west of Islamabad, and killed in February 2009, with the Pakistani Taliban later releasing a video of his beheading.