As major supermarkets continue to pull strawberry punnets from their shelves, the Queensland government has offered a reward of $100,000 for information leading to the arrest of the person responsible for contaminating the fruit with sewing needles.
"There are significant leads in relation to that matter", he said, without providing details of the case.
"Sadly, there are those in the community who perhaps don't understand the harm they're doing".
Authorities say they don't know whether the later cases were connected, or whether they were copycats.
Initially three incidents in Queensland had been reported to police on Thursday.
Food manufacturing plants are said to be equipped with metal detectors, but these are mainly created to identify pieces that may contaminate products accidentally during processing.
‘Defender of Israel, American patriot’ Ari Fuld mourned by United States diplomats
Four people died initially and a fifth died of her wounds at a hospital Saturday afternoon, authorities said. Sources also reported that Israeli forces immediately opened fire and shot the Palestinian youth.
Queensland Police told national broadcaster ABC the contamination of the strawberries - usually sold in small plastic boxes called punnets - was done "obviously to injure somebody".
He said police were still interviewing the people involved.
Needles have been found inside strawberries in two more Australian states, police said on Monday, broadening a health scare that has caused supermarkets to recall brands and farmers to dump fruit amid the peak growing season.
Aldi and Coles supermarkets across the country have removed all strawberries from shelves as a precaution and New Zealand stores have also stopped supplying Australian grown strawberries to customers.
However, NSW Police have now said that the contamination might have affected four more brands: Love Berry, Donnybrook Berries, Delightful Strawberries and Oasis.
An urgent recall was originally issued on Wednesday following the discovery of needles planted inside the fruit, with Queensland's Chief Health Officer Dr Jeannette Young advising anyone who has purchased strawberries from the Berry Liscious and Berry Obsession brands to dispose of their fruit immediately.