Detectives are looking at CCTV, as they investigate whether a string of armed robberies were linked at Lake Macquarie.
Strike Force Woonooka was set up to investigate four robberies at three separate service stations in the region last month.
About 3am on June 10, a man armed with a large knife entered a service station on Main Road, Cardiff and threatened an employee.
He stole cash and cigarettes before running away, and was last seen headed north on Lowry Street.
Just before 11am on June 12, a man armed with a large knife entered a service station on Main Road, Edgeworth, and threatened an employee, before stealing cash and cigarettes.
He was last seen walking south on Garth Street.
About 3.30am on June 29, a customer was trying to enter a service station on Main Road, Cardiff, when another man approached him armed with a knife.
The armed man attempted to enter the store, however was unsuccessful and ran away north, on Lowry Street.
Just after 7pm on July 9, a man with a large knife entered a service station on Collier Street, Redhead, and threatened an employee.
He stole cash and cigarettes, and was last seen heading south on Woods Street.
In each of the incidents, there were no reports of injuries.
Strike force detectives are now investigating whether all four incidents are linked.
They’re looking for a man described as being of medium build, wearing dark-coloured clothing and a face covering.
Anyone with information or dashcam footage from the around the times and nearby locations of the incidents is urged to contact police.