At this point, once the type of bomb was determined, the technicians would have sought specialist advice, he said. NSW Police said it received advice from British military experts and the Australian Federal Police.
What was left of the collar bomb found on the body of Brian Wells after it exploded following a bank robbery. Photo: AP"You would [then] get your screwdriver out and your pliers and you'd take it apart ... there's a possibility you can set off the bomb if you don't know what you're doing and you get it wrong," he said.
"But that's why they went to so much trouble to get intelligence and information about the bomb before they went down there."
Mr Hearn said the technicians would have tried to release the person from the collar before attempting to defuse it either manually or with a robot. It is not clear if a robot was used in this case.