British Ambassador to Saudi Arabia, Mr Cowper-Coles told BBC Radio 4's Today programme: "It is impossible to imagine the terrorists escaping without some sort of understanding with the security forces.
I think they were allowed to escape purely because of their connections with the internal security at Saudi
"One cannot be clear exactly what happened. We are still piecing it together. The Metropolitan Police haven't finalised their internal report.
"But it does look as though there was something that enabled the terrorists to get out of that compound, which was surrounded by a very large number of security forces".
Mr Hamilton's brother, Douglas, also criticised Saudi security forces for allowing militants to escape.
He added: "The thought that 40 special security people went in through various doors and in through the roof and they could not contain three men appears to be totally beyond belief.
"I think if you equate that with the number of the SAS required to take this little lot out, it would have been very small and I think the result would have been conclusive.
"I think they were allowed to escape purely because of their connections with the internal security at Saudi".
news.bbc.co.uk/1/hi/uk/3636926.stm"Oil Man Died in 'Cold-Blooded Atrocity' - Inquest
By Matt Adams, PA News
A British oil executive shot dead in a suspected al Qaida attack in Saudi Arabia was the victim of a “cold-blooded atrocity”, his devastated wife said today.
The full horror of the attacks on May 29 in which 61-year-old Michael Hamilton and 21 others died, emerged today at his inquest.
The father-of-two, originally from Kilmarnock in Ayrshire, was shot at least nine times as he sat in his car at the headquarters of a major oil firm in Al Khobar where he had worked since 1989.
The Islamic militants shot him in the chest at close range and then tied his body to the back of their car before dragging it through the streets for more than a mile.
Mr Hamilton’s body was found near a roundabout after the rope snapped, the inquest heard today.
Moments before the 7am killing, Mr Hamilton, who lived in Rye, East Sussex when visiting the UK, dropped his wife Penelope to a nearby residential compound near the Araba Petroleum Investments Corporation, where he worked.
In a statement read after the inquest in Hastings at which a verdict of unlawful killing was returned today, Mrs Hamilton said: “Michael was the victim of a cold-blooded atrocity.
“He had worked in Saudi Arabia for many years and was widely known and respected. He was going about his business in Al Khobar when he was targeted by terrorists.
“In Michael, we have lost a loving husband, son and father. He was kind and generous and he was dedicated to his work for an Arab company. He was a friend of Saudi Arabia.”
The widow, flanked by her son Matthew and Mr Hamilton’s brother Douglas, stood nearby as the statement was read by family solicitor Philip Peacock.
Detective Superintendent Kim Durham, of Scotland Yard’s anti-terrorist branch, told the inquest that he and several other British officers went to Al Khobar following the murders to support Mrs Hamilton and record her husband’s final moments.
He said at the time of his death, Mr Hamilton was talking to a guard at the security gate when the terrorists pulled up and opened fire through the windows of his Ford company car, killing both him and the guard instantly.
The group then marched into the office building, forcing cleaning staff to direct them to the whereabouts of any western workers.
Several shots were fired by the militants, dressed in combat gear, before they left the building.
They then fired at a mini-bus full of children blocking the exit gate. It burst into flames, killing one 10-year-old Egyptian girl.
The terrorists drove out of the complex but returned, pulled up next to Mr Hamilton and then tied his body to the back of their vehicle with rope.
Mr Durham said: “It was always their intention to tie someone to the back of their vehicle. It was at a roundabout that his body was found.”
A second attack was launched almost simultaneously by a separate group of militants at another petroleum compound around three miles away.
There several westerners were executed as well as some Muslim staff.
At a third compound in the city, it is thought the same gunmen that killed Mr Hamilton launched another attack. They took hostages before the siege was broken after a 12-hour stand-off.
Mr Durham told East Sussex Coroner Alan Craze the Saudi authorities had concluded that the attack was the work of al Qaida, and that one of the attackers resembled a man featured on the website of a group which later claimed responsibility for the atrocities.
Speaking after the inquest, Mr Durham said some suspects had been killed in gun battles in Saudi Arabia, while others had been detained and questioned. No one has yet been found guilty of the attacks.
Mr Craze said when reaching his verdict: “There is a peculiar perverse logic in picking targets who are not military or who are not exploiting the Arab resources, but who are voluntarily requested by Arab nations to live amongst them and to give them their own expertise to assist them in legitimate commercial enterprise.
“Mr Hamilton’s death was not just a tiny chapter in the war on terror, but the pointless gunning to death of someone’s husband, relative and friend.
“He was a wholly innocent man who did nothing but try to help those for whom he worked.”"news.scotsman.com/latest.cfm?id=3366559Edited to add: comments by British Ambassador to Saudi Arabia