Police identify British-born attacker, victim count rises to four

By Michael Holden and Estelle ShirbonLONDON (Reuters) - The attacker who ploughed a car through a throng of pedestrians and then stabbed a policeman outside Britain's parliament was named on Thursday as Khalid Masood, a British-born man who was once investigated by MI5 intelligence officers over concerns about violent extremism.The attack was the deadliest in Britain since 2005, when 52 people were killed by Islamist suicide bombers on London's public transport system.It followed a series of Isl