The investigation into the murder of David Amess, Conservative lawmaker, was being led by counterterrorism officers. The Metropolitan Police stated that the attack was terrorist and that the initial investigation had revealed "a possible motivation linked to Islamist Extremism."

Amess, aged 69, was attacked at midday Friday at a Methodist Church in Leigh-on-Sea. This town is about 40 miles (62 km) east of London. Paramedics attempted to save him but failed. The suspect was arrested by police and a knife was found.

The suspect was being held under suspicion of murder, but they didn't identify him. Although police stated that they believed the suspect was acting alone, they are not looking for anyone else in connection to the murder.

Five years ago, Jo Cox was killed by a far right extremist in her small-town constituent. This renewed concern about the dangers politicians face as they represent voters. British politicians are generally not provided with police protection when they meet their constituents.

Amess received tributes from all political parties and the community where he lived for many decades. At a Leigh-on-Sea church, residents paid tribute to him.

The Rev. said that he had a great East London spirit, having no fear and being able talk to people at their level. Jeffrey Woolnaugh spoke at the vigil attended by around 80 people. "I would not say that all politicians are adept at this."

Boris Johnson, Conservative Prime Minister, stated that he and his Cabinet were "deeply stunned and heart-stricken."

Johnson stated that David was a man who believed strongly in the country and its future. Johnson expressed his sadness at the loss of Johnson.

The prime minister refused to say whether the attack had meant that politicians required tighter security. He said, "We must really abandon the police to continue their investigation."

Amess was a member of Parliament Southend West (which includes Leigh-on-Sea) since 1997. He had also been a lawmaker since 1983. This made him one of the longest-serving politicians at the House of Commons.

He was a social conservative from the right, and was well-liked. He worked tirelessly for his constituents to get Southend declared a municipality.

Amess, who left a wife and five kids, was knighted in 2015 by Queen Elizabeth II for his services, and became Sir David.

In an avalanche of questions about the security of lawmakers, flags at Parliament were reduced to half-staff.

Lindsay Hoyle, House of Commons Speaker, said that "this is an incident which will send shockwaves throughout the parliamentary community as well as the whole country." "In the days ahead, we will have to discuss and analyze MPs' security, and any steps that may be taken. But for now, our thoughts, prayers, and condolences are with David's loved ones, friends, and colleagues."

Although violence against British politicians is not common, there are growing concerns about the bitter polarization in the country's political landscape.

Cox, a Labour Party lawmaker was fatally attacked and shot in northern England just one week before the country’s divisive Brexit referendum. In recent years, many people were jailed for threatening lawmakers.

British lawmakers are protected inside Parliament by armed police. Security was increased after an Islamic State-inspired attacker fatally stabbed a police officer.

However, politicians do not have this protection in their constituents. His website contains the locations and times of Amess' open meetings with constituents.

Over the past 20 years, two other British lawmakers were attacked during their "surgeries", regular meetings where constituents can voice concerns and complain.

Stephen Timms, Labour legislator, was attacked in the stomach by a student who had been radicalized by al-Qaida-linked sermons online.

A man with a sword attacked Andrew Pennington and Nigel Jones, Liberal Democrat in 2000. Pennington was killed, and Jones was wounded in the attack on Cheltenham in England.

Conservative former Prime Minister Theresa May tweeted that Amess was killed because of "tragic day" for democracy, and Tony Blair, former Labour Prime Minister, said he was shocked and horrified.

Nicola Sturgeon, Scottish First Minister, of the Scottish National Party, said on Twitter that "In a democracy politicians must be accessible, open to scrutiny but no one should have their lives taken while working for or representing their constituents."

Kim Leadbeater is Jo Cox's sister, and she is now a member in Parliament. She said that it was "horrific," that Amess' family was going through what hers was.

She said, "They will think about it every day for the rest their lives."

"I now find myself working as a politician, trying to do good for people, and I think it's really important that you get good people into public life. But this is the risk we all take, and many MPs will be scared.