Detectives from Geelong Crime Investigation Unit have arrested four teenagers as part of their ongoing investigation into an armed robbery at a Lara service station last month.

Police were called to the Mill Road business just before 1.40am on 24 July following reports four male offenders, allegedly armed with hammers, smashed their way into the store and stole cash and cigarettes.

It is believed a fifth offender remained in a waiting vehicle, being a silver Mercedes-Benz believed to have been stolen from an aggravated burglary in Balwyn North on 22 July.

This morning investigators executed search warrants at addresses in Brookfield, Wyndham Vale, Mill Park and Epping.

A 16-year-old Brookfield boy, 16-year-old Wyndham Vale boy, 17-year-old Mill Park boy and a 17-year-old Epping boy were arrested during the operation.

Detectives are also investigating whether the armed robbery is linked to an aggravated burglary in Fairview Avenue, Camberwell on 25 July.

The teens remain in custody and are assisting police with their enquiries into all three incidents.