The killing of Edwin Dyer marks a big – and disturbing – change in the Sahara. This is the first time a hostage has been executed in the region. The two women kidnapped with Mr Dyer were released, as were the two Canadian diplomats abducted a couple of months previously. Money likely changed hands in those cases but this latest death isn't about the British policy of not paying ransoms to terrorists. It is far more complicated than that.

The official version of the truth is that all the kidnappings in this desert region have been carried out by the Salafist Group for Preaching and Combat, now trading as al-Qa'ida in the Maghreb.

My view, however, is that they are the legacy of the West's actions in the Sahara at the beginning of this decade when they stoked up – or rather fabricated – the terrorist threat so they could justify a second African front in the war on terror. There was already the Bin Laden link in Somalia and they wanted one on Africa's west coast, too.

I didn't think the kidnappers would dare kill a British hostage but they clearly wanted to show that they pose a real danger, that they are genuine terrorists. Terrorism in the Sahel, which began as Western-backed propaganda, has become a self-fulfilling prophesy. Mr Dyer's murder is part of an immensely complex and long-running story. It started in 2002 when there were plans by Algerian security forces to kidnap Western tourists to make it look like there was terrorism in the Sahara. In 2003, 32 Europeans were taken hostage in a series of abductions run by a man known as El Para, an agent of the Algerian intelligence service, the DRS.

The Algerians organised the hostage takings and they did it in cahoots with the Americans – although Washington always denied it. There followed a whole range of US-backed military initiatives which just happened to coincide with the time when energy-hungry Western countries were trying to reduce their reliance on Middle East oil and find alternative energy sources.

After those initial, eye-catching kidnappings – and more importantly, the surge in US-backed counter-terrorism operations that followed – it went quiet. But trouble erupted again in February 2008 when two Austrians were taken hostage. The Austrians were captured in Tunisia and taken down to Mali, a move which would be impossible unless the Algerian security forces were complicit. I was involved in the negotiations to free them, dealing with the point man for Abdelhamid Abou Zeid, who was involved in the 2003 kidnappings. He is listed on UN documents as a known al-Qa'ida member but I have seen considerable evidence which suggests that he is an Algerian DRS agent. And surprise, surprise, his name comes up again in the case of Mr Dyer.

It seems the genie is starting to escape the bottle of its own accord. What the West set up in the glory days of the war on terror seems to have spiralled out of control. The culpability for Mr Dyer's murder rests as much with Western intelligence services as with al-Qa'ida.

The author is a professor of social anthropology at the School of Oriental and African Studies in London and the author of The Dark Sahara: America's War on Terror in Africa