LONDON (AP) - London's police commissioner expressed regret Sunday for the slaying of a Brazilian electrician by officers who mistook him for a suspect in the recent terror bombings, but he defended a police shoot-to-kill policy as "the only way" to stop would-be suicide bombers.
Metropolitan Police Commissioner Sir Ian Blair also said there were similarities between the explosives used in Thursday's failed bomb attacks and those detonated July 7. But he said investigators still had no proof the two strikes were linked.
"The equipment in the bombs had all the elements that it should have but it didn't work," Blair told Sky News TV, referring to the explosives that failed to detonate properly Thursday on three subway cars and a double-decker bus.
"It had some similarities" to the devices used in the July 7 bombings on three subway trains and a double-decker bus, killing 56 people, including four suicide attackers.
When asked if Thursday's attacks were connected to those of July 7, Blair replied, "We have no proof that they are linked but clearly there is a pattern here."
Two of the suspected July 7 bombers, Mohammad Sidique Khan and Shahzad Tanweer, went whitewater rafting in Wales three days before the attacks, according to the National Whitewater Centre.
Police refused to comment on a British Broadcasting Corp. report, attributed to unidentified officials, that said authorities were examining whether those involved in Thursday's attacks were on the same trip.
Police have made two arrests after Thursday's botched attacks. Officers have not released the identities of those detained.
But Blair added that officers were "still anxious for any sighting of the four individuals" who carried out Thursday's strikes. Closed-circuit TV stills of the suspects were made public last week.
Police carried out several controlled explosions to dispose of a suspect package found in northwest London, which they said may have been linked to devices used in the botched July 21 attacks. They refused to elaborate.
The man shot Friday at the Stockwell subway station was identified as Jean Charles de Menezes, 27. Witnesses said he was wearing a heavy, padded coat when plainclothes police chased him into a subway car, pinned him to the ground and shot him five times in the head and torso in front of horrified passengers.
Blair initially said Menezes was "directly linked" to the investigation of Thursday's attacks, but police then said Saturday he had no connection to the bomb attempts.
"This is a tragedy," Blair said Sunday of the shooting. "The Metropolitan Police accepts full responsibility for this. To the family I can only express my deep regrets."
He also defended the shoot-to-kill policy, saying such action only applied when lives were believed to be at risk.
"I am very aware that minority communities are talking about a shoot-to-kill policy," he said. "It's only a shoot-to-kill-in-order-to-protect policy."
Blair said British police have drawn from the experiences of other countries, including Sri Lanka, that have dealt with suicide attackers.
"The only way to deal with this is to shoot to the head," Blair said. "There is no point in shooting at someone's chest because that is where the bomb is likely to be."
Blair spoke of the problem his officers faced.
"What we have got to recognize is that people are taking incredibly difficult fast-time decisions in life-threatening situations," he said. "What's most important to recognize is that it's still happening out there. There are still officers out there having to make those calls as we speak."
Police said Menezes attracted police attention because he left a building that was under surveillance after Thursday's attacks. They said he was then followed by surveillance officers to the station, and his clothing and behavior at the station added to their suspicions. Menezes was wearing a heavy coat while temperatures were in the 70s.