By the late 1970s, the Church of Scientology ran the largest private intelligence agency in the world. This was the Guardian's Office. When many of their top executives were busted for infiltrating the US government, DM stepped in to "disband" the old GO. But actually he just kicked out a few and reorganized the rest into the Office of Special Affairs conducting character assassination operations to defame whistle blowers exposing the crime, corruption and human rights abuses within the Church. For example, OSA uses various cut outs (legal firms) to hire private investigators to harass people, defame them on dozens of websites — all of who's domain names were purchased on the same day, etc.
OSA Int is located on on the 10th floor of the Hollywood Guarantee Building in Los Angeles and has offices in each continental area, with a representative (supposed to be) in each org called the "Director of Special Affairs" or DSA for short.