LONDON — Both of the suspects accused of butchering a British soldier during broad daylight on a London street had long been on the radar of Britain's domestic spy agency, though investigators say it would have been nearly impossible to predict that the men were on the verge of a brutal killing.
Still, counter-terrorism officials said they are reviewing what — if any — lessons can be gleaned from the information they had leading up to the slaying Wednesday.
Authorities in the U.S. have similarly pledged to review their procedures in the wake of the Boston Marathon bombing, with the Boston police commissioner saying that cities should consider deploying more undercover officers and installing more surveillance cameras.
The British review comes amid an outpouring of grief over Wednesday's slaughter of 25-year-old Lee Rigby of the 2nd Battalion The Royal Regiment of Fusiliers. Rigby, who had a two-year-old son, had served in Afghanistan. Detectives say they do not believe the attackers knew him or that he was specifically targeted, but they are still investigating.
"We are looking at decisions that were made and reviewing whether anything different could have been done," said a British counter-terrorism official who spoke on condition of anonymity because he was not authorized to speak about the investigation. "But you can't put everyone under surveillance who comes on to the radar."
Prime Minister David Cameron said Thursday that the Intelligence and Security Committee would review the work of agencies such as Britain's domestic spy agency, MI5, in the wake of the attack "as is the normal practice in these sorts of cases."
In Britain, security officials operate under the "principle of proportionality," which means there needs to a compelling reason before any type of surveillance is undertaken.