A former US attorney appeared before Carrick-on-Shannon District Court today on charges of possessing images of child pornography in Sligo.
Detective Julie Coyne gave evidence of arresting Gerard Gilligan, who has an address in New Jersey.
He is accused of possessing 646 images of child pornography on 1 March 2009 in a house at Union Place in Sligo.
Det Coyne told Judge Kevin Kilrane that at 6.15pm on Monday, Mr Gilligan was handed over to her custody in New York by members of the US Marshall Service.
She said she formally arrested Mr Gilligan at Dublin Airport at 7.14am this morning.
Det Coyne told the court that she cautioned Mr Gilligan and he replied: "I just didn't know about it."
She sought a remand in custody to Sligo District Court on Thursday for service of the book of evidence.
Defence solicitor Laura Spellman said she was not making an immediate application for bail but "possibly" would be on Thursday.
Judge Kilrane formally remanded Mr Gilligan in custody to appear before Sligo District Court on Thursday.