It was presumably founded by Norman Harvey Blackwood Sr. in the beginning of the 20th century as a reaction to the rise of activity around the Cthulhu Mythos in Arkham.
The Agency: This "investigator" faction comprises the Blackwood Detective Agency, law enforcement agencies, and others involved in criminal justice.
Central Intelligence Agency | National Security Agency | European Space Agency | International Atomic Energy Agency | United States Environmental Protection Agency | Federal Emergency Management Agency | United States Agency for International Development | detective | United States Information Agency | Blackwood | Environment Agency | Ace Ventura: Pet Detective | Detective fiction | Detective Comics | International Energy Agency | William Morris Agency | Blackwood, Caerphilly | Richard Diamond, Private Detective | advertising agency | The No. 1 Ladies' Detective Agency | Detective | Ace Ventura: Pet Detective (TV series) | Xinhua News Agency | private detective | Frederick Hamilton-Temple-Blackwood, 1st Marquess of Dufferin and Ava | Defense Intelligence Agency | Creative Artists Agency | Canadian International Development Agency | Blackwood's Magazine | Advertising agency |