The killer, who MailOnline is not naming because of operational reasons on the request of the police, lived in a block of flats in Barking and also played table tennis with youngsters.
A neighbour told MailOnline the man who was pictured in an Arsenal shirt lying dead on the street outside the Wheatsheaf pub in Borough Market near London Bridge was a father of at least two children.
The murderer managed to put on such a front with those close to him that local parents would even trust him to be alone with their children, which used to happen regularly.
ISIS tonight claimed responsibility for the attack, 24 hours after the three terrorists were shot dead, saying the three men were a 'squadron of fighters from the Islamic State'.
The Barking jihadi was described as 'a nice guy' by a neighbour who saw him hold a door open for an old lady two days before slaughtering innocent members of the public in the third Islamic terror attack in just over 10 weeks in the UK.