Speaking outside Scotland Yard on Wednesday night, Mark Rowley, the Met's senior anti-terror officer, said of PC Palmer: "Today in Westminster we saw tragic events unfold and our thoughts are with those who lost loved ones, those who were injured and all those affected by this attack".
"Carlos" went on the rampage to try to win the release of his wife after her arrest in 1982 by French police, staging five bombings in Paris and elsewhere in the subsequent months that killed 12 people and injured hundreds.
Khalid Masood, a lone, British-born attacker, who was known to police and had a string of convictions, was named as responsible for the attack on Westminster on Wednesday.
Khan described Masood as "evil and twisted", and said: "The victims were people who came from all corners of our world..."
"We've seized 2,700 items from these searches, including massive amounts of computer data for us to work through", Rowley said, adding that contact had been made with 3,500 witnesses.
The auto initially ploughed into several pedestrians on Westminster Bridge with other people fleeing in panic.
He was then shot by armed police as he tried to stab another officer.
Five people have died - a police officer, the attacker, a woman named as Aysha Frade, 43, U.S. tourist Kurt Cochran and 75-year-old Leslie Rhodes succumbed to his injuries in hospital a day after the attack. Two people remain in a critical condition, Rowley said, with a number of others still receiving treatment for serious injuries. A British-born Muslim convert, Masood had shown up on the periphery of previous terrorism investigations that brought him to the attention of Britain's MI5 spy agency.
Shortly before 15:00 UTC, multiple shots followed by screaming were reported outside London's Houses of Parliaments. The first reports came in from political reporters barred from leaving the premises.
THE incident at Westminster yesterday, now classified as a terrorist act, happened at an area where tourists flock to for a view of the Westminster Palace and Big Ben, and to take in the sights from the bridge.
Nevertheless, the pavements on the bridge over the Thames river which leads to the iconic Big Ben tower has nearly no protective devices, and the gate through which MPs walk or drive their cars into Parliament remains strangely vulnerable.
Defences around Whitehall, an area of 1km in radius in central London where Parliament and most key government departments are to be found, have already been strengthened considerably during the past two decades.
In July 2005, four British Islamists killed 52 commuters and themselves in bombings on the London's transport system in what was London's worst peacetime attack.
And they have offered little detail about him and what might have led to the attack. German Chancellor Angela Merkel reaffirmed Germany's support for the United Kingdom "in the struggle against all forms of terrorism". Counter-terrorism chief Mark Rowley said one policeman, three civilians and the attacker died.
The Islamic State group has claimed responsibility for the attack on Westminster Bridge and at Parliament. Yet in the face of the contemporary wave of Islamist-inspired terror attacks, it is easy to forget that Europe has been through similar torments in the past and emerged, peace restored, with its democratic institutions intact.
His bravery was praised by many MPs, who had gathered in the House of Commons chamber to listen and respond to Theresa May's statement on the terror attack. "We need to say to [the terrorists] they are getting it wrong, completely wrong".