Britain mourns slain lawmaker Jo Cox, throwing EU referendum into limbo

Britain mourns lawmaker Jo Cox a day after a man wielding a gun and knife killed the 41-year-old mother of two in a brazen street attack that has thrown the June 23 referendum on European Union membership into limbo.

Police investigating possible political motive; previous threats to Labour MP led to arrest in March

Britain is mourning lawmaker Jo Cox a day after a man wielding a gun and knife killed the 41-year-old mother of two in a brazen street attack that has thrown the June 23 referendum on European Union membership into limbo.

Cox, a supporter of Britain staying in the EU, was shot and repeatedly stabbed in her own constituency near Leeds in northern England on Thursday by a man who witnesses said had shouted "Britain first."

She was pronounced dead just over 48 minutes later by a doctor working with a paramedic crew trying to save her life. A 52-year-old man was arrested nearby, and weapons including a firearm were recovered.

The killing prompted a halt to campaigning in the EU referendum. Though the motives of the killer were not immediately clear, some speculated that sympathy for Cox could boost the Remain campaign, which has fallen behind Leave in recent days.

Police said they were not in a position to discuss the motive of the attack. 

They said Cox had previously contacted police after receiving "malicious communications," and a man was arrested in March. 

That man — not the 52-year-old now in custody — "subsequently accepted a police caution," investigators said. 

In London, the Union Jack was flying at half-mast over the Houses of Parliament, Downing Street and Buckingham Palace, while a steady stream of people came to lay flowers at Parliament Square, on the sidewalk near a large photo of Cox. 

Others stood quietly, reading the heartfelt messages left by mourners.

"We are so sorry," said one handwritten note attached to a bunch of white roses.

On a white placard growing dark with signatures, someone wrote, "You can't kill democracy."

"She had the same political beliefs as me, and this sort of thing doesn't happen often here," said a man who had come to place some roses.

"I just wanted to remember her."

A police officer carries bunches of flowers at the scene of the killing of Labour MP Jo Cox in Birstall near Leeds, U.K., on Thursday. (Phil Noble/Reuters)

Shaista Ahmad Sheehan, a peer of the House of Lords, also started her day by placing some flowers on the sidewalk.

She worked with Cox on an all-party group that Cox had set up to help people trapped within Syria who were not receiving any aid.

"She was an inspirational leader," Sheehan said, visibly emotional. "I'm so sad that she's gone."

Politicians paid tribute to Cox and expressed shock at the killing, as did leaders across Europe and the world.

Prime Minister David Cameron said the killing of Cox was a tragedy.

"We have lost a great star," said Cameron, who visited Cox's constituency on Friday, joined by Labour Leader Jeremy Corbyn. "She was a great campaigning MP with huge compassion, with a big heart. It is dreadful, dreadful news." 

Corbyn said Parliament will be recalled on Monday to allow lawmakers to pay tribute to Cox. 

Parliament has not been sitting since Thursday, to allow campaigning ahead of the referendum. 

In Birstall, hundreds of people attended a vigil at a local church. 

"Jo believed in a better world and she fought for it every day of her life with an energy and a zest for life that would exhaust most people," said Cox's husband, Brendan Cox.

"She would have wanted two things above all else to happen now: one that our precious children are bathed in love and two, that we all unite to fight against the hatred that killed her."

Residents gathered in the central square where a mountain of flowers was steadily growing — just a few feet from the police cordon set up around the spot where Cox was attacked.

Four police officers moved closer to the memorial in order to make people safe, one of them said.

"It's very sad she's been taken in such circumstances — a young mother, a young wife, everything to look forward to," said Abu Momoniat, 59, who lives in the area.

"To be taken in such a small town where she's been serving … It's just a tragedy, really," she told CBC's Nahlah Ayed.

"Everywhere the mood is just so down at the moment, everyone is so shocked," said another resident, Aisha, who did not want her last name used. She broke down in tears as she spoke.

Neo-Nazi link?

Media reports, citing witnesses, said the attacker had shouted out "Britain first," which is the name of a right-wing nationalist group that describes itself on its website as "a patriotic political party and street defence organization."

The deputy leader of the group, Jayda Fransen, distanced it from the attack, which she described as "absolutely disgusting."

West Yorkshire's elected police and crime commissioner said "our information is that this is a localized incident, albeit one that has a much wider impact."

The killer was named by media as Thomas Mair.

A U.S. civil rights group, the Southern Poverty Law Center (SPLC), based in Alabama, said on its website that it had obtained records showing a Thomas Mair had links with the neo-Nazi organization National Alliance (NA) dating back to 1999.

The SPLC posted images showing what it said were purchase orders for books bought by Mair, whose address is given as Batley, from the NA's publishing arm National Vanguard Books in May of that year. The orders included a manual on how to build a pistol, it said. Batley is a community less than five kilometres from Birstall. 

Family members, including his brother, said that Mair had not expressed strong political views, the Guardian reported.

"He has a history of mental illness but he has had help," the newspaper quoted Scott Mair as saying.

"I am struggling to believe what has happened. My brother is not violent and is not all that political. I don't even know who he votes for."

Labour MP Yvette Cooper, centre, hugs a priest at St. Peter's Church after a vigil in memory of Jo Cox, on Thursday. (Phil Noble/Reuters)

Neighbours were quoted by media as describing a man who had lived in the same house for at least 40 years and helped locals weed their flowerbeds.

Gun ownership is highly restricted in Britain, and attacks of any nature on public figures are rare. The last British lawmaker to have been killed in an attack was Ian Gow, who died after a bomb planted by the Irish Republican Army (IRA) exploded under his car at his home in southern England in 1990.

With files from The Associated Press and CBC's Nahlah Ayed