Before he killed four people in Britain’s deadliest attack since the 2005 London bombings, Khalid Masood was considered by intelligence officers to be a criminal who posed little serious threat. A British-born convert to Islam, Masood had shown up on the periphery of previous terrorism investigations that brought him to the attention of Britain’s MI5 spy agency. But the 52-year-old was not under investigation when he sped across Westminster Bridge on Wednesday, mowing down pedestrians with a hired car before running into the grounds of parliament and fatally stabbing an unarmed policeman. He was shot dead by police. "Our investigation focuses on understanding his motivation, his operation and his associates,” Britain’s senior counter-terrorism police officer, Mark Rowley, told reporters. A European government source familiar with the investigation said Masood’s name had cropped up about five years ago on the margins of an MI5 counter-terrorism investigation but interest in him had swiftly dissipated. At the

time of the attack, British authorities had "no intelligence about how he got to this point,” the source said, adding that investigators were now rushing to piece together his background and contacts.

Agencies