A man and a woman were being questioned in Donegal last night by officers of the Criminal Assets Bureau in relation to suspected money-laundering activities.
Both are from Scotland but have been living in Co Donegal for the past seven years, according to Supt Michael Duffy of Ballyshannon.
The two were arrested on Thursday morning and the period of their detention was extended yesterday evening.
Under the legislation that established the bureau, they can be held for up to a week without charges being preferred.
The man is aged 57 and was being held last night in Ballyshannon Garda station. The woman, who is in her early 50s, was being held in Donegal town.
The Criminal Assets Bureau was established in July 1996 in the aftermath of the killing of the journalist Veronica Guerin. The bureau was set up to identify assets derived from criminal activity and to take appropriate action to deprive or deny persons of such assets or benefits.