The drugs unit based in Letterkenny have arrested one man and are continuing their investigations as a result of an operation in Co Monaghan this weekend.
A man from the Kilmacrennan area was arrested and €12,500 worth of cocaine seized.
The suspect was arrested on a drugs run from Dublin to Donegal. He was arrested before he crossed the Border at Aughnacloy, Co Tyrone.
The operation follows months of work by drugs squad officers trying to trace the gang which had been flooding Letterkenny with cocaine.
The gang is suspected of adding dangerous chemicals when ‘cutting’ the cocaine before selling it here in Donegal.
A house near Leitir, Kilmacrennan was searched over the weekend by drugs unit officers supported by gardaí in Milford.