Who was the man behind the south London stabbing attack?

A man shot dead by police after he stabbed people in South London had recently been released from prison after serving a sentence for terrorism-related offences.

Sudesh Amman was under active police surveillance at the time of the attack.

Dr David Lowe, a former counter terrorist detective and now senior research fellow at Leeds Beckett University Law School, explains how police were operating.

(Photo: Forensic officers in Streatham after a stabbing attack. Credit: Simon Dawson/Reuters)