LONDON — A lawmaker who campaigned for Britain to stay in the European Union was killed Thursday by a gun- and knife-wielding attacker in her small-town constituency, a tragedy that brought the country's fierce, divisive referendum campaign to a shocked standstill.
Jo Cox, a 41-year-old Labour Party legislator who praised the contribution of immigrants to Britain and championed the cause of war-scarred Syrian refugees, was attacked outside a library in Birstall, northern England, after a regular meeting with constituents.
Police would not speculate on the attacker's motive, but Clarke Rothwell, who runs a cafe near the scene of the slaying, told the BBC and Britain's Press Association that the assailant shouted "Britain first!" several times. Police did not confirm that account.
Witnesses described a man shooting Cox several times and then stabbing her as she lay on the pavement. Police said they had arrested a 52-year-old man and were not looking for anyone else.
"Our working presumption ... is that this is a lone incident," said Dee Collins, acting chief constable of West Yorkshire Police.
British security officials said the shooting didn't appear to be related to international terrorism, but domestic terrorism has not been ruled out.
Residents identified the suspect to the BBC and other media as Birstall resident Tommy Mair.
Neighbors said Mair was a quiet man who did gardening jobs for local people.
