Man Shot Dead by British Police Was Innocent Brazilian Citizen

"We've all seen the four images -- surely their brothers, sisters, parents and friends must know who these people are," he said.

Officers had staked out a number of potential suspects and locations after the bombing attempts in hopes of catching the assailants. One site was an apartment complex in Tulse Hill, near Stockwell, an ethnically mixed blue-collar neighborhood.

The man who emerged Friday morning was wearing a padded, blue-fleeced jacked and dark baseball cap that covered his features and made him appear suspicious as well as harder to identify, police officials said. Officers from a specialist undercover firearms unit trailed him as he took a bus to the Stockwell station. As he headed into the station, the officers bolted after him, and the man ran toward the platform, witnesses said. He stumbled into a subway car and three undercover operatives with handguns piled on top of him. One opened fire, according to witnesses, who gave graphic accounts of what one newspaper termed "an execution."

Ian Blair, commissioner of the Metropolitan Police, said Friday that the man was linked to the probe into the abortive bombings. He also told reporters that officers had ordered the man to halt and had opened fire only after he failed to obey. But none of the witnesses reported hearing any warning.

The shooting took place under shoot-to-kill guidelines adopted after the Sept. 11, 2001, attacks in the United States under the name "Operation Kratos" to deal with the threat of suicide bombers. While officials would not publicly discuss the guidelines, sources told British reporters that a senior officer is authorized to deploy special armed units to track and, if necessary, shoot dead suspected suicide bombers. The officers are advised to shoot such assailants in the head to keep them from setting off explosives.

The guidelines are based in part on procedures used by the Israeli authorities in intercepting suicide bombers. But police officials insist officers still must follow the law, which only allows the use of reasonable force in preventing a crime. The guidelines of the Association of Chief Police Officers say police should not open fire except when someone's life is in danger and there is no other way to stop the assailant.

The shooting of the wrong man fueled the sense of unease that has gripped London since the bomb attacks Thursday.

Meanwhile, a 17-year-old boy was remanded in custody, charged with an arson attack on the home of Germaine Lindsay, whom police alleged was one of the London suicide bombers.