The fatal stabbing of UK lawmaker David Ames was declared a terror incident by authorities, who said the Metropolitan Police's Counter Terrorism Command is now leading the investigation.
The conservative lawmaker was stabbed multiple times Friday at one of his bimonthly meetings with constituents, which was being held at Belfairs Methodist Church. Amess had been an MP for 38 years.
"He was treated by emergency services but, sadly, died at the scene," Essex police said in a statement.
Early Saturday morning, Deputy Assistant Commissioner Dean Haydon, senior national coordinator for counter terrorism policing, declared the attack an act of terrorism and said in a statement that investigators had linked a possible motive to Islamist extremism.
Police added that a 25-year-old man had been arrested on suspicion of murder. The man is being held in custody and police are not looking for anyone else.
Investigators are also searching two locations in London as part of their investigation
This attack comes five years after MP Jo Cox was fatally shot and stabbed in northern England. Her husband, Brendan Cox, tweeted his condolences and said the attack brings everything back for him.
"The pain, the loss, but also how much love the public gave us following the loss of Jo. I hope we can do the same for David now," Cox tweeted.
Amess was 69 years old and leaves behind a wife and five children. He was knighted by Queen Elizabeth in 2015 for his political and public service.
Prime Minister Boris Johnson paid tribute to Amess, calling him "one of the kindest, nicest, most gentle people in politics."
"He also had an outstanding record of passing laws to help the most vulnerable," Johnson said. "Whether the people who are suffering from endometriosis, passing laws to end cruelty to animals or doing a huge amount to reduce the fuel poverty suffered by people up and down the country.
"We’ve lost today a fine public servant and a much loved friend and colleague our thoughts today are very much with his wife and his children and his family."
Carrie Johnson, the wife of Prime Minister Boris Johnson, shared her condolences for Amess.
With union flags being lowered to half-mast above Downing Street in honor of Amess, tributes from ministers have started pouring in.