Port Lincoln Police are investigating a series of car and home break-ins after 13 incidents were reported overnight.
Police were called to properties on Oxford Terrace, Matilda Street, Eric Avenue, Highview Drive, Walkley Road, Hambidge Street, Stanley Grove, Mena Place and Flinders Avenue.
In a majority of the incidents, thieves entered properties through unlocked house doors and windows along with unlocked vehicles.
Items stolen include house keys, car keys and mobile phones.
And in several cases, car keys were taken from houses then used to unlock secured motor vehicles.
A witness reported seeing a suspicious man on Highview Drive between 5.45am and 5.50am.
He is described as being of Aboriginal appearance, about 18 years, tall, slim build and wearing a green hooded jumper.
Police will be deploying additional patrols in the Port Lincoln area.
Police would also like to remind local residents that while leaving windows and doors open during the hot weather for a cool evening breeze may sound like a good idea, home owners should ensure their doors and windows are locked at all times.
The community is urged to immediately report any suspicious activity by calling The Police Assistance Line on 131 444.
Police are asking anyone that has had their house broken into or property stolen, to report it to police asap at the Port Lincoln Police station on 1/5 Liverpool St, Port Lincoln SA 5606 or contact 86883020.
Anyone with information about these offences is asked to contact Crime Stoppers on 1800 333 000 or online at www.crimestopperssa.com.au