Video footage from the terror attack shows a bystander holding a narwhal tusk, which had been ripped from a wall inside Fishmongers Hall where Khan, Mr Crilly and others were taking part in a prisoner rehabilitation conference.
This is where Khan started his rampage, and Mr Crilly has shed light on the details of what happened inside the venue before the terrorist was chased out onto the street where he was shot dead by police.
He told the Daily Mirror: “At the bottom of the stairs stood Usman Khan with his two knives out jumping about like a mad man. It didn’t take too long to realise what was going on.
“Without stereotyping, he had a big beard, two knives, shouting ‘Allahu akbar’. He was wearing a suicide belt.”
Mr Crilly also said that an armed Khan told them: “I’m going to kill you all,” before lunging at crowds with his knives.
Talking about the burglary in Manchester that went wrong and ended with one of his co-defendants killing a pensioner with a single punch, he said: “My life has been spent wishing that day never happened.”