The manager of a fast food outlet in Derry was taken hostage by a group of armed men in his north Donegal home shortly after 7.30pm yesterday in a so-called tiger kidnapping.
His partner was forced to travel across the border to retrieve money from the business.
Following a hand-over on the border, both victims were set free unharmed but distressed from the ordeal.
Superintendent Vincent O'Brien is trying to trace the whereabouts of two cars: "What we are interested in are the movements of the grey Ford Focus from about 7.30 between Muff, the Waterside and back to Bridgend; and from Bridgend back to Muff again.
"And in respect to the yellow Honda Jazz, from Muff to the Bridgend/Waterside area," he added.