Aden Hashi Ayro was one of the most feared and notorious figures in Somalia whose powerful influence in the country showed most starkly the depths of anarchy and brutality to which it has sunk.

Tall, painfully thin and with what local journalists who had met him described as anger-filled eyes, Ayro’s brief life — he is believed to have been in his early thirties when he was killed by an American air strike — was one of unremitting violence.

With little formal education, Ayro became an Islamist fighter as a teenager in the early 1990s after the overthrow of the veteran Somali dictator Mohammed Siad Barre. He is said to have taken part in every major battle involving Islamist militias since then. A protégé of Shiekh Hassan Dahir Aweys, who led the Islamist adminstration which was overthrown by the Ethiopian army — with American endorsement — at the end of 2006, Ayro then emerged as a key leader of the Islamist insurgency and was, according to Washington, al-Qaeda’s top operative in Somalia.

Aden Hashi Ayro is reported to have received military training in Afghanistan, where he almost certainly came into contact with senior al-Qaeda figures, possibly including Osama bin Laden himself. He was said to be close to Abu Talha al-Sudani, a Sudanese national named by Washington as al-Qaeda’s east African chief. The United States has welcomed Ayro’s death as an important success in its “war on terror”, but many Somalis believe western intelligence exaggerated his links to al-Qaeda and few have any doubts that there will be plenty of candidates ready to take over his feared al-Shabaab militia.

Whatever his exact connections to global terror, Ayro was a notorious killer, believed responsible for a string of atrocites. These included the murder of several foreign aid workers, the shooting dead in Mogadishu in 2005 of a BBC journalist, Kate Peyton, and the digging up of a colonial-era Italian cemetery in the Somali capital. At the same time, again according to local journalists who met him, Ayro considered himself a “soldier and teacher” in a Holy War against foreigners and infidels. He never addressed a public rally and rarely gave interviews.

According to Somali intelligence, Ayro dropped out of school at a young age to wash cars but soon became caught up in the street violence in Mogadishu which followed the ousting of Siad Barre in 1991. This was the start of a period of vicious clan fighting which saw a disastrous and abortive American attempt to restore order and the failure of a United Nations peace-keeping mission.

In the mid-1990s Ayro came under the influence of Hassan Dahir Aweys, a leader of his Hawiye clan whose extremist Islamist group, al-Itihaad al-Islamiya (AIAI) was, according to Washington, funded by bin Laden and involved in the bombings of the US embassies in Kenya and Tanzania in 1998. It was Aweys who is supposed to have sent Ayro to Afghanistan for training by the Taleban, where he learnt insurgent tactics and how to use explosives. Ayro is said to have been with the Taleban at the time of the American invasion following the September 11 attacks in the United States in 2001.

Back in Somalia by 2004, Ayro was charged by Aweys with setting up a hard-line youth wing within the newly-formed Islamic Courts Union (ICU) which was intent on imposing Sharia law across the country. Al-Shabaab — literally “the lads” — apparently had the remit to assassinate foreigners and opponents who in Islamist eyes were co-operating with the internationally-recognised transitional authorities. The group numbered several thousand who were reported to be paid $70 a month by Ayro.

By the start of 2005, Ayro was operating openly in Mogadishu. In January, he ordered the desecration of the graves of dozens of Italians in a colonial cemetery in the Somali capital, causing international condemnation and rejection of Ayro by some of his clan elders. But his militant activities increased and a month later he was blamed for the killing of the BBC news producer Kate Peyton. He had almost certainly been behind the earlier murders of a number of foreign aid workers.

By the middle of 2006, the Islamic Courts Union was in control of Mogadishu and much of Somalia and Ayro’s power appeared to increase as Aweys began to take control of the ICU leadership. Al-Shabaab was reported to have taken delivery of a big consignment of arms from Eritrea and Ayro was said to have personally selected hundreds of Somali volunteers sent to Lebanon to fight alongside Hezbollah forces against the Israeli army.

The picture inside Somalia changed dramatically at the end of 2006 when the Ethiopians invaded, officially at the invitation of the internationally-recognsied but impotent, transitional authories. The Islamists were routed within days with their top leaders fleeing to Yemen and Eritrea, but Ayro is reported to have led stiff resistance to the Ethiopians in the Baidoa area and was among a hard core of perhaps a thousand fanatical Islamists who stayed.

Ayro soon resurfaced to declare jihad on the occupying forces and al-Shabaab began to wage an Iraq-style insurgency engaging in almost daily attacks on Ethiopian forces. His enemies now included any moderate Islamists willing to engage in US and UN-sponsored efforts to bring about reconciliation talks which could lead to an Ethiopian withdrawal.

In recent months, Ayro’s fighters had stepped up their attacks on Somali towns, typically holding them for a few hours, freeing prisoners and then withdrawing with captured weaponry.

Last year Ayro survived an American air strike near the southern port of Kismayo, emerging with only minor injuries. But the Americans continued on Ayro’s trial, possibly helped by Somali clan elders alienated by the al-Shabaab leader’s arrogance and brutality. On May 1 a US air strike — reportedly four Tomahawk cruise missiles fired from a navy ship off the Somali coast — on the central Somali town of Dhussa Marreeb killed Ayro, his brother and a number of other top al-Shabaab leaders. A spokesman for al-Shabbab announced: “Our brother, Aden Hashi, has received what he was looking for — death for the sake of Allah, at the hands of the United States.” He vowed retaliation.

Aden Hashi Ayro, Somali Islamist insurgent leader, was born in the early 1970s. He died on May 1, 2008, aged about 35