Armed Crime Taskforce detectives are appealing for information from the public in relation to a string of armed robberies at newsagencies and post offices across Melbourne during the past eight months.

Detectives now believe the robberies, which occurred in Croydon, Rosanna, Preston, Strathmore and Mitcham between May and September 2013, are linked.

Acting Detective Sergeant David O’Riley from the Armed Crime Taskforce said looking at the incidents collectively indicated that they were part of a series.

“Looking at the incidents as a series rather than in isolation, we’ve been able to make the connection and have taken carriage of the investigations from the local crime investigation units and embona taskforces,” A/D/Sgt O’Riley said.

“There are certain similarities between the incidents that suggest they are being carried out by the same group of offenders and we’re appealing for public assistance to help identify and locate them.

“On each occasion, a group of two to three males in their early 20s with dark skin and covered faces have produced knives and demanded cash from the shop attendants.

“On one occasion at a newsagency in Strathmore on 6 September, two male victims were also violently assaulted.

“While the offenders have used different vehicles to flee the scene, on each occasion the vehicle involved has had an obscured number plate or no number plate attached.

“We have concerns about the violent nature of the offending and need the public’s help to identify and arrest these people before they commit any more offences.”

Police have released CCTV of the robbery in Strathmore in September. They have also released a still image of a 1998 green Ford Fiesta, believed to be involved in the robbery at Preston in August, and a 1999 black Jeep Gran Cherokee believed to be involved in the incident in Mitcham in September.