LONDON (AFP) - British MP Jo Cox, a pro-EU lawmaker who campaigned for Britain to stay in the EU and more aid for Syrian refugees, was killed in a street attack on Thursday (June 16).
Weapons, including a firearm, have been recovered from the scene of the incident in her constituency and the sole suspect is being held by police.
This is what we know so far:
1. About Jo Cox
Cox, 41, was the member of parliament representing the constituency of Batley and Spen in West Yorkshire, northern England, where she grew up.
A University of Cambridge graduate, she was the Oxfam aid agency's policy chief before entering parliament in the May 2015 general election.
She was a prominent campaigner for refugee rights and spoke out in favour of immigration in a powerful first speech in parliament.
Cox co-chaired the cross-party parliamentary group on Syria.
She was campaigning for Britain to stay in the European Union in the June 23 referendum.
She married Brendan Cox, a former adviser to prime minister Gordon Brown on Africa and international development. He was formerly the director of policy and advocacy at the Save the Children charity.
She is also survived by their two young children, Lejla and Cuillin.
They lived on a converted barge near Tower Bridge in London. Her husband and children took part in a pro-EU flotilla on Wednesday against a River Thames protest by anti-EU fishermen.
2. What happened?
The attack took place in Birstall, a large village in her constituency. It happened outside the library, where she regularly held meetings with her constituents.
Police said they were called at 12.53pm (7.53pm Singapore time) on Thursday to reports of an incident where a woman in her 40s had suffered serious injuries and was in a critical condition.
British media cited locals as saying she had been shot and stabbed by a man shouting "Britain first".
Police said weapons, including a firearm, were recovered from the scene.
Cox was pronounced dead at 1.48pm by a doctor working with a paramedic crew that was attending to her.
A 77-year-old man sustained injuries that were not life threatening.
3. Who is the attacker?
Officers arrested a 52-year-old man at the scene. British media said he had been named locally as Thomas Mair, whom one neighbour called a "loner".
Police said they were not looking for anyone else in connection with the attack, which was described as "a localised incident".
They said a full investigation would try to establish a motive. Police said they were speaking to a large number of witnesses.
A United States civil rights group reported that Mair had a "long history with white nationalism", having been a dedicated supporter of the National Alliance - the once premier neo-Nazi organisation in the US - for decades.
4. Were there other similar attacks on British MPs?
Five MPs have now been killed in office since World War II.
Ian Gow had been the last, assassinated by Irish Republican Army paramilitaries in 1990.
The IRA killed Anthony Berry in the 1984 bombing of Brighton's Grand Hotel where prime minister Margaret Thatcher and her cabinet were staying.
The IRA shot dead Northern Irish MP Robert Bradford in 1981, while former Northern Ireland secretary Airey Neave was murdered by paramilitaries in 1979.
Labour MP Stephen Timms was stabbed in the stomach in 2010 by an Islamic extremist but survived the attack.
5. Reactions so far
Husband Brendan Cox: "Today is the beginning of a new chapter in our lives. More difficult, more painful, less joyful, less full of love.
"Jo believed in a better world and she fought for it everyday of her life with an energy, and a zest for life that would exhaust most people.
"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."
"We've lost a great star. She was a great, campaigning MP with huge compassion, with a big heart.
"She had a great track record of caring about refugees and had taken a big interest in how we can look after Syrian refugees and do the right thing in our world.
Prime Minister David Cameron: "It's right that we are suspending campaigning activity in this referendum."
Labour Party leader Jeremy Corbyn: "The whole of the Labour family, and indeed the whole country, is in shock and grief.
"We have lost a much loved colleague, a real talent and a dedicated campaigner for social justice and peace."