Career
Commissioner Costigan was involved in the security for the visit of then President John F. Kennedy to Ireland in 1963. Three death threats had been received and Commissioner Costigan urged his subordinates not to overlook the possibility of threats no matter how unlikely they were. He regarded the visit as the most important the country had since independence.
In 1963, then Minister for Justice Charles Haughey accused the Commissioner of "talking through his hat" after learning that only 15% of criminals were fingerprinted (petty criminals were not).
The Murphy Report criticised Commissioner Costigan for his handling of allegations of child abuse by French Edmondus (pseudonym).
Scotland Yard had contacted him concerning images that the priest had sent to be developed in the United Kingdom. Commissioner Costigan asked Archbishop John Charles McQuaid to handle it because a priest was involved and he claimed "Gardaí could prove nothing".