Known wolf.
Via Reuters:
LONDON (Reuters) – Sudesh Amman, the man shot dead by police in what officials described as a terrorism incident in south London, had been jailed for promoting violent Islamist material and had encouraged his girlfriend to behead her parents.
Amman, 20, was named by British police as the attacker who stabbed two people before he was shot dead by armed officers who had been carrying out surveillance on him.
In November 2018 he pleaded guilty to possession of terrorist documents and disseminating terrorist publications, and the following month he was sentenced to more than three years in prison.
He was 17 and living at home with his mother and younger siblings when he first began committing terrorism offenses, according to authorities. Police became aware of his activities in April 2018 and he was arrested by armed officers in a north London street a month later.