The WA Police Commissioner has been unable to explain the “risk-based decision” he believes justified the strip search and aggressive physical restraint of a woman in the East Perth Watch House in 2013.

The incident was the subject of a long investigation by the Corruption and Crime Commission (CCC), made public this week, which concluded the search and the force used to restrain her was unlawful.

The woman, Joanne Martin, had been arrested for disorderly conduct in Northbridge and ended up in the watch house, naked, pinned to the floor and being hit repeatedly by officers as they attempted to restrain her.

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But in an extensive media conference following the release of the CCC’s report, Police Commissioner Karl O’Callaghan made it clear it was Ms Martin, not his officers, who were in the wrong.

“What happened in this case was the woman was asked to comply with a strip search and pushed back on the strip search. And so that escalated the amount of force that is necessary,” he told reporters.

The commissioner said the decision to conduct a strip search had been made by watch house supervisors based on their assessment of the risk Ms Martin posed to herself and others.

The CCC report makes clear that the power to strip search a watch house detainee “is not open-ended”.

The report said such a search must be considered “reasonably necessary”, and also provided discretion for a basic search to be conducted instead.

WA Police Commissioner Karl O’Callaghan explained the affair at a news conference. Photo: ABC

“That condition exists for the benefit of the citizen, and cannot be arbitrarily waived by individual police auxiliary officers or certain watch house teams,” the CCC said.

Mr O’Callaghan was asked by reporters on Thursday what risk police believed Ms Martin posed in order to justify a strip search.

“Well, look, I don’t know exactly why the officers chose that, but the supervisor of the watch house, if you look at the CIA, the Criminal Investigation Act, can make a risk-based decision, under section 135 to search a person,” he said.

The CCC report concluded that Ms Martin posted no threat to anyone.

‘Officers have to make those decisions’

Mr O’Callaghan was asked if he thought Ms Martin posed a threat to officers.

“I wasn’t there,” he said.

He was also asked whether he thought she seemed to pose a risk based on the CCTV vision, where Ms Martin appeared calm and compliant.

“I think the vision is not sufficient for me to answer a question about a risk-based decision they would have made on the night,” he said.

“The officers have to make those decisions and they make them all the time.”

He maintained the escalation of force was prompted by Ms Martin’s refusal to comply with the strip search direction.

“Well, when she was asked to participate in a strip search, she resisted. And when the police officers went to do what they had to do, the resistance started to elevate, and that’s what happened,” he said.

The CCC report had a very different conclusion.

The report rejected the idea that the incident was due solely to Ms Martin’s refusal to cooperate with officers and instead found failures in proper process and sensible decision-making which occurred prior to Ms Martin’s refusal to cooperate.