- Video report by ITV News Security Editor Rohit Kachroo
A man who once lived in the same town as the Westminster attacker has revealed how he remembers him being "quite troubled".
Adrian Baker, 51, knew Khalid Masood as 'Adrian' over 17 years ago when he lived in Northiam, East Sussex, saying he "caused a bit of aggravation in some of the pubs".
Mr Baker, who has lived in the town for 25 years, told ITV News that he recalled Masood once stabbed a pub landlord in a local pub.
Masood was jailed for two years over the attack in 2000.
The 52-year-old reportedly converted to Islam after he left the town, though Mr Baker said he doesn't recall him being religious at all.
"I'm amazed, it beggars belief doesn't it I mean he certainly wasn't religious then, I'm fairly certain there was nothing religious about him at all," said Mr Baker.
"In fact you'd have thought he was anti-establishment as I remember it."
The schoolboy footballer grew into a troubled adult spending time in prison for a string of violent crimes.
The 52-year-old's family moved around during his youth including to upmarket Tunbridge Wells, Kent.
A childhood classmate of Masood described him as a popular pupil who "liked to party".
Stuart Knight was in the same class as the then Adrian Ajao at Huntleys Secondary School for Boys in Tunbridge Wells for five years.
Mr Knight, 52, said: "He was a very nice guy, down to earth, liked by everyone around him.
On hearing the news of his former classmate's actions in London, Mr Knight added: "I am really shocked. I spent five years in his class at school, for him it's totally out of character."
"I am in shock - that is not sympathy for what he has done, he was a nice guy and I'm surprised he turned and did what he did."
What do we know about the Westminster attacker's life?
- Born in Kent 25th December 1964
- Named Adrian Elms also known as Adrian Russell Ajao
- Attended Huntley School For Boys in Tunbridge Wells
- When he left school he was convicted for criminal damage aged 18
- Over the course of 20 years he was convicted for a string of offences including assault and possession of an offensive weapon.
- He served time in Wayland Prison, Lewes Prison, Ford Prison
- After converting to Islam he used the names Khalid Choudry, then Khalid Masood
- Worked in Saudi Arabia as an English teacher in 2005 and then again in 2008
- Back in Britain he lived in Luton and then in Birmingham
Another person who knew Masood over a decade ago told ITV News "there was always something unpleasant" about him.
Alice Williams, a landlady also from Northiam, said: "He was always intimidating, very, very intelligent, never rude or unpleasant but there was always something unpleasant about him".
The landlady, who still lives in the town, also referred to the attack Masood carried out on the pub landlord 17 years ago saying he was "quite obviously unrepentant about it shall we say".
Ms Williams added that she heard about another incident reportedly carried out by Masood in which he slashed the tyres of multiple vehicles following a disagreement.
Questions remain over where Masood became radicalised with speculations pointing to one of his stints in prison or during time that he spent in Saudi Arabia.
At some point after his radicalisation he came to the attention of MI5, but only as a peripheral figure according to Prime Minister Theresa May.
The killer most recently appeared to be based in the West Midlands, but also spent time in London, Sussex and Luton.
After his armed onslaught on Wednesday, police searched a three-storey townhouse in the Winson Green area of Birmingham. Neighbours said Masood lived there for around seven months until December last year.