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The owner of a caravan found packed with explosives in Sydney's north-west is in police custody on unrelated matters, as the commissioner blasted the leaking of the find as "compromising" the investigation.
The caravan was discovered on the side of a road in Dural on January 19 by a member of the public, who alerted police.
It had been left on the side of Derriwong Road for several weeks.
READ MORE: What we know about the caravan found with explosives in Sydney
Two people of interest were already behind bars when the caravan was found, Webb said.
One of those people has been identified as Tammie Farrugia, who was arrested last month after an alleged antisemitic attack in Sydney.
Her name was also on the search warrant which allowed police to raid a property in Dural following the discovery of the caravan.
A second man who was jailed on drugs and weapons charges last month has also been identified as a person of interest in the case.
No charges have been laid against either over the discovery of the explosives.
The investigation was only made public yesterday, after a number of media reports.
It comes as police also investigate several new incidents of antisemitic graffiti in Sydney's east, including on a Jewish school.
The explosives the caravan contained were said to be capable of causing a "mass casualty event" with a 40-metre diameter blast, police said, and there were indications they were intended for use in an antisemitic attack.
Several arrests have been made but police say they are on the "periphery" of the investigation.
"In addition to the information that has been provided, on the basis that it's now in the public domain, I can confirm that the owner – registered owner of that caravan – is a person that is in custody on unrelated matters," Webb said today.
She said that there was also no detonator found with the explosives.
"So the risk to the public has been mitigated very early on," she said.
Deputy Commissioner David Hudson said the caravan owner had been arrested in early January for alleged offences investigated by Strike Force Pearl.
"At the time the caravan was located he was in custody," he said.
He said the man being in custody gave police time to sift through the available evidence before deciding whether or not to proffer charges related to the caravan.
At least 100 officers from multiple agencies, including the Australian Federal Police and ASIO, have been assigned to the caravan investigation.
Multiple search warrants have been carried out.
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Webb and NSW Premier Chris Minns both defended the decision to keep the investigation clandestine.
"The fact this information is now in the public domain has compromised our investigation and has been detrimental to some of the strategies we may have used," Webb said.
Hudson said police were having to "reposition" themselves after the investigation went public.
"The risk has been mitigated to the point that we don't think obviously that the caravan and those explosives and that particular individual are a threat to the community," Hudson said.
"But there are ongoing threats that we have seen overnight."
He said there were potential links between the caravan incident and some other antisemitic incidents being investigated by Strike Force Pearl.
Speaking to Ben Fordham on 2GB, Hudson indicated there were more arrests to be made.
"Until you charge everybody involved there is the potential for incidents to occur," he said.
He said police were trying to trace the source of the explosives, which consisted of Powergel, used "almost exclusively" in the mining industry.
Earlier, Minns said he could not "responsibly" assure the community the threat was over.
"I would love to give assurances that the threat has passed … but I can't do that," he told Today.
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Debate over secret investigation
Speaking on Today, former NSW Police officer and terrorism expert Peter Moroney said there were multiple reasons police would have kept the investigation a secret until yesterday.
"As (NSW Police) Deputy Commissioner (David) Hudson explained in his press conference, police will often not put out information on the pure point of remaining in a tactical or strategic advantage over the criminals or the criminal syndicates that we're working," he said.
"We don't want to advertise what we know or don't know, so that's certainly not unusual."
Moroney said the explosives, which are understood to have been reported stolen from a mine site, should be easy to track.
"The problem might be, for example, if it was stolen, say 12 months ago, we've got a 12-month black hole where we simply just don't know where those explosives have been, or potentially going towards what state they are being transferred into before they become an actual explosive itself," he said.
Minns has unequivocally described the incident as one of "terror", while NSW Police have confirmed they are treating it as a terrorist act.
Co-CEO of the Executive Council of Australian Jewry, Peter Wertheim, told Today the operational police need for clandestine investigations needed to be balanced against the public's right to be informed.
"The whole idea of the people who perpetrate these acts is to create fear, and more than fear, panic and hysteria," he said.
"So when people are kept in the dark, they jump to all sorts of conclusions and they speculate, and that just encourages the very panic that the perpetrators are trying to create."
He also pointed out that while the perpetrators appeared to be targeting Jews, the amount of explosives in the van posed an indiscriminate danger to anybody in its vicinity.
"Until we understand more about who is behind these incidents and particularly yesterday's reported incident, we just don't know what their motives are," he said.
"We don't know exactly where they're coming from."
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