[4] Superintendent Daniel Ryan headed the detectives answering to Sir Henry Lake, chief commissioner of the Dublin Metropolitan Police (DMP).
On 15 July 1865, Irish-American plans for an IRB rising in Ireland were discovered when the emissary lost them at Kingstown railway station.
In his book "The Spy in the Castle", David Neligan, an IRA double agent who infiltrated G Division, suggests that much of their activity was unprofessional and dependent upon casually-recruited local informers plus conspicuous English officers whose wartime experience in Cairo and elsewhere had little relevance to Dublin conditions.
Broy was a double agent with the rank of Detective Sergeant (DS) [6][7] and worked as a clerk inside the G division branch.
There, he copied sensitive files for Collins and passed this material on to the latter through Thomas Gay, the librarian at Capel Street Library.
On 7 April 1919, Broy smuggled Collins into G Division's archives in Brunswick Street, enabling him to identify "G-Men", seven of whom would be killed by the IRA.