The Cairo Gang was a group of British military intelligence agents who were sent to Dublin during the Irish War of Independence to identify prominent members of the Irish Republican Army (IRA) with, according to information gathered by the IRA Intelligence Department (IRAID), the intention of disrupting the IRA by assassination. Originally commanded by British Army General Gerald Boyd, they were known officially as the Dublin District Special Branch (DDSB) and also as D Branch.

The Squad, nicknamed the Twelve Apostles, was an Irish Republican Army (IRA) unit founded by Michael Collins to counter British intelligence efforts during the Irish War of Independence, mainly by means of assassination. The Squad engaged in executing informants, police active in harassment of IRA personnel, enemy agents and worked in counterespionage.