London attack: Khalid Masood - what we know about killer
The man police say was responsible for the Westminster attack has been formally identified as 52-year-old Khalid Masood.
Born in Kent in December 1964, Masood most recently lived in the West Midlands.
The BBC believes he also lived in recent years at two addresses in Luton and one in east London.
The Metropolitan Police says he was also known by a number of aliases.
Previous convictions
The BBC believes that Masood hired the car used in the attack earlier this week from the Spring Hill branch of Enterprise in north Birmingham. He described his profession as a "teacher".
Within an hour of hiring the Hyundai, he is thought to have contacted the company to say he no longer needed the car. What happened next is completely unclear - until he drove north across Westminster Bridge, ploughing into pedestrians on the western pavement.
"Masood was not the subject of any current investigations and there was no prior intelligence about his intent to mount a terrorist attack," Scotland Yard said.
"However, he was known to police and has a range of
previous convictions for assaults, including grievous bodily harm, possession of offensive weapons and public order offences."
Masood's first conviction came when he was 19-years-old in November 1983 for criminal damage. His last conviction was in December 2003 for possession of a knife. He had never been convicted of a terrorism offence.
In her statement to MPs, the prime minister said that the attacker was British born and that "some years ago" he was "once investigated in relation to concerns about violent extremism".
She went on: "He was a peripheral figure. The case is historic - he was not part of the current intelligence picture. There was no prior intelligence of his intent - or of the plot."
Petty criminality
We don't know at this stage what that particular investigation was and how he was connected to it.
Here are just some of the possibilities of what that could mean:
* He was an associate or friend of a main suspect who was being monitored in some form - but turned out, at the time, to not apparently have any extremist leanings
* He could have been closer to an inner circle of aspiring extremists - but he personally was not considered to be a risk and so the operation was focused on others
* There could have been more concerning intelligence about his ideology and intent - but there was nothing that could make a criminal charge - and in time he was discounted as a serious threat
He could, at the highest end, have been arrested in the past as part of an operation and later released without charge.
His last conviction came when he was 38 or 39. In general terms, that's quite late on in life for your average angry young man stuck in a world of petty criminality, violence and robbing.
Possession of a knife can cover a multitude of criminal intentions - from going equipped to commit a burglary or assault or, as some people claim, "self defence".
Did he go straight because, like many criminals, he had started a family and settled down? Or was there something deeper in his personality driving that violence - and the possibility that he would return to it?
And that raises the final question: what was the trigger for this attack?
http://www.bbc.co.uk/news/uk-39373766