British lawmaker David Amess, a member of Boris Johnson's ruling Conservative Party, died after being stabbed several times at a constituency meeting east of London.
Amess, 69, a member of Parliament who represented Southend West in Essex, was attacked at around midday Friday by a man who walked into a meeting with voters from his electoral district being held in a Methodist Church in Leigh-on-Sea.
"He was treated by emergency services but, sadly, died at the scene," Essex police said.
Here's what else we know about the investigation:
The suspect: A 25-year-old man arrested on suspicion of murdering Amess on Friday is believed to be a British national with Somali heritage, official sources have told the PA news agency. "A 25-year-old man was quickly arrested after officers arrived at the scene on suspicion of murder and a knife was recovered," Essex police said.
The investigation: The UK's Counter Terrorism Command will lead the investigation into the murder, police said later Friday. "It will be for investigators to determine whether or not this is a terrorist incident. But as always, they will keep an open mind," Ben-Julian Harrington, Chief Constable of Essex Police, told reporters.
"Tragic day for our democracy": Former Prime Minister David Cameron said Amess was "a kind and thoroughly decent man" and "the most committed MP you could ever hope to meet." "Words cannot adequately express the horror of what has happened today. Right now, my heart goes out to David's family," Cameron said. Cameron's successor Theresa May added the news was "heartbreaking" and "a tragic day for our democracy."
Britain's second murdered lawmaker in five years: The killing was another grim moment in Britain's political history. It marks the second murder of a sitting British lawmaker in five years, after Labour MP Jo Cox was killed in her constituency in 2016, and has reignited discussions about the safety of the UK's elected officials.
Boris Johnson was joined by all of his living predecessors in expressing shock, and lawmakers from every corner of the political spectrum spoke of their sadness, their concern, and their anger after another of their colleagues was killed while meeting with his constituents. "David was a man who believed passionately in this country and in its future," Johnson said in a statement from Downing Street. "We lost today a fine public servant."
About Amess: He entered Parliament in 1983, initially representing the Basildon constituency. He served continuously in the House of Commons since then, making him one of the longest-serving lawmakers in the chamber. Amess was knighted in 2015 for his political service. He supported Britain's departure from the European Union, and his main areas of expertise were animal welfare and pro-life issues, according to a biography on his website.
In March, Amess asked a question in Parliament about how to stop "senseless murders" with knives, after a teenager in his constituency was killed in a knife attack.