Home secretary orders review of parliamentarians' security measures, and says police and authorities to implement 'immediate changes and measures'

Ali Harbi Ali, 25, a British citizen and the son of a former Somali government official, was arrested at the crime scene; was not previously known to the British security forces

In era of polarized politics, terrorism threats, social media, public accessibility has become fraught with risk

British PM, opposition leader make joint visit to church where Conservative lawmaker was killed; MPs press for protection after murder of 2nd colleague in 5 years

Authorities say suspect, reported to be of Somali descent, found to have 'a potential motivation linked to Islamist extremism'; police carrying out searches at London addresses

David Amess hailed as a true friend of Israel and a staunch supporter of the exiled opposition to Iran's Islamic government

Authorities say investigation into killing of MP David Amess still in early stages, with no possible motive announced; shaken politicians call to rethink security procedures