Warrnambool police Acting Sergeant ​​Lana Roberts said offenders used a wrought iron chain at 4.25am on Sunday to attempt to lock in the residents in their home behind the milk bar.

They had placed the chain under the door so it couldn't be opened.

Then offenders opened the rear screen door and a wooden door to the milk bar, which triggered an audible alarm.

​Both vehicles at the property were also searched but it appeared that nothing was taken.

Acting Sergeant Roberts said officers had obtained excellent security camera footage which was being reviewed.

Anyone with information, or who saw anything suspicious in the area about the time of the incident, are requested to contact the Warrnambool police station or Crime Stoppers on 1800 333 000.

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