"Opportunistic" criminals have struck 12 times in five days across Ipswich.
A new warning has been issued to the public to remain vigilant after reports of theft, break-ins and interfering with vehicles.
Inspector Naomi Lofthouse said: “Having your car broken into can be very distressing but there are a few steps you can take which will deter thieves and keep your valuables safe.
"Many of these crimes are opportunistic and we want to make it harder for criminals.”
Nine of the twelve vehicles were entered.
Five vehicles in Ashcroft Road, Burns Road, Dales Road and Waterford Road had items taken.
This included sunglasses, cash, a purse and wallet over a three day period between August 17 and August 20.
Police also received reports three vehicles in Elmcroft Road, Willowcroft Road were targeted in the early hours of August 18.
There were three reported incidents in Cromer Road on August 22.
Suffolk police also recorded four incidents of vehicles being searched in Everton Crescent, Whitehouse Road and Shakespeare Road between August 19 and August 22.
Suffolk Police recommends you always lock your vehicle and keep windows fully closed, secure anything outside the vehicle, don't leave valuables in the vehicle and ensure electronics and mountings are hidden from view.
They also suggest vans are at a high risk of being targeted for tools left inside, if you have to leave them, mark them clearly or keep in a lockable box or cabinet.
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