Police dogs and horses have joined the hunt for who was responsible for putting two batches of the deadly explosive TATP in a West Australian estuary.
The police presence was still high at Australind near Bunbury on Sunday as the investigation continued into who might have placed the highly volatile chemical in the Leschenault estuary and why.
The Australind jetty was reopened to the public on Saturday, with State Crime Commander Scott Higgins saying police are comfortable the area is now clear.
However, the public is being urged to remain vigilant and report any suspicious activity.
"Residents in Australind will continue to see a high-level police presence in their community as additional officers remain in the community conducting the investigation," Cmdr Higgins said.
The explosive - widely used by terrorist organisations in recent years - was discovered in Australind, south of Perth, early last week.
Police initially believed the crystalline substance found by a member of the public on Tuesday night was for making drugs, and so it was transported to Perth to be stored at the major crime headquarters in the city centre.
But when the nature of the substance was discovered, buildings were evacuated and the explosives were delicately transported before controlled detonations at a Perth racetrack.
Navy divers were back in the water on Friday morning, with a second suspicious package prepared for controlled detonation.
TATP, known as "Mother of Satan", is highly volatile and can be manufactured from household ingredients.It's believed three kilograms of the chemical was found at Australind. Each of the explosives in the 2005 London bombings weighed at least 2.5kg.