Last night a premises on the town's main street was broken into while a house in the Gransha area was also targeted.
There were a further four robberies in the town at the weekend. One man has been arrested and charged - he remains in custody.
Gardai are now keen to speak to a second man who they believe was involved in a number of the robberies that remain unsolved.
He was born circa 1993, is 5ft 7 of medium to stocky build and has a freckled complexion - he is know to have access to a mountain bike and number of addresses in Buncrana.
Superintendent Eugene McGovern made this appeal on The Shaun Doherty Show: