The man responsible for the Westminster terror attack has been named as Khalid Masood by Scotland Yard.
Police said he was not the subject of any current investigations and there was "no prior intelligence about his intent to mount a terrorist attack".
As Scotland Yard mounts a major investigation into the 52-year-old, here's what is known so far about Masood:
He was born in Kent on Christmas Day to a single mother in 1964
He was named Adrian Russell Ajao at birth but soon adopted the surname Elms, reportedly from his stepfather
He most recently lived in the West Midlands but spent periods living in London, Sussex and Luton
He is understood to be married with several children, according to a neighbour
He used a number of aliases, including the name Khalid Choudry after converting to Islam
He had no prior convictions for terrorism offences
He had a string of convictions for offences including GBH, possession of offensive weapons, and public order offences
He spent time behind bars at Lewes Prison in East Sussex, Wayland Prison in Norfolk and Ford open prison in West Sussex
He was first convicted in 1983 for criminal damage
He was last convicted in 2003 for possession of a knife
The 2003 incident saw him stab a man in the nose outside a nursing home in Eastbourne
He reportedly masked his criminality on a CV which claimed he was an experienced English teacher
He claimed he had worked across the world, including Saudi Arabia - the Royal Embassy of Saudi Arabia confirmed he worked in the country from November 2005 to November 2006 and again from April 2008 to April 2009
He is understood to have never worked as a teacher in any of England's state schools
Masood is thought to have acted alone and been inspired by "international terrorism".
He rented a grey Hyundai i40 - a 4x4 - from car hire firm Enterprise, reportedly its Solihull branch.
Masood stayed in the Preston Park Hotel in Brighton on the south coast of England the night before the attack before driving up to London.
He ploughed the car into pedestrians on Westminster Bridge, before smashing it into the railings encircling the Palace of Westminster.
He jumped out of the vehicle and, armed with two large knives, fatally stabbed Pc Keith Palmer as he entered the grounds.
He was shot dead by another police officer after attacking Pc Palmer.
Prime Minister Theresa May told the House of Commons a day after the attack that he was a "peripheral figure" and "not part of the current intelligence picture."