One of the London Bridge terrorist attackers taught primary school children that non-Muslims were the "worst creatures" and told them it was OK to lie to their parents "in a state of war".
A police counter-terrorism officer said the actions of Khuram Butt at Eton Community School, in Ilford, East London, were suggestive of "grooming type behaviour".
Butt was one of the three terrorists who carried out the London Bridge terrorist attack on 3 June 2017, in which eight people died and 48 people were injured. He was shot dead by police with the other two terrorists on the night of the attack.
He was employed in a voluntary position as an Arabic memorisation teacher at an after-school club at Eton Community School – an independent Muslim day school for pupils between 3 and 11, which was closed down in August 2017.
The news came as the head who hired him, Sophie Rahman, was struck off by a professional conduct panel of the Teaching Regulation Agency for leaving her pupils "vulnerable to grooming for radicalisation".
The revelations about Butt's activities at Eton Community High are contained in Ms Rahman's prohibition order, which includes details from a police counter-terrorism officer who gave evidence to the panel.
According to the officer, one child who went to Butt's lessons recalled him saying that "the worst creatures are the Kuffar (non-believers)".
Terrorist 'mentioned war'
The child also said that Butt had told them "it was OK to lie to their parents under two circumstances: firstly, when they do not want to upset them and secondly when there is a state of war".
The officer recalled that during the interview with police and social services in which the child recounted their experiences, the child's "mother became more and more horrified about what [the child] told him to the point that she became so distressed that she said she had to leave with her daughters".
In a subsequent interview, the mother told him that "these were not the kind of things she expected her eight-year-old daughter to be taught or spoken to about".
The police officer told the panel: "Mention of the word war really alarmed me – if that is what Mr Butt was teaching there is no doubt he was referring to jihad (holy war)."
The police officer told the panel that Butt's behaviour was consistent with grooming for radicalisation.
He said he was "uncomfortable with the reference to lying and to justifying lying (to parents)".
"In my experience, that is the type of language and manipulation that you might see from abusers who try to create trust and build unhealthy relationships with young people. I perceive it as potentially being grooming type behaviour."
The panel said it was in "complete agreement with this analysis of the situation from an experienced professional".
The officer told the panel that "it has never been possible to ascertain with absolute certainty all of the pupils who did have contact with Mr Butt, which is in itself a concern".