The Estonian Internal Security Service has primary investigative jurisdiction in some offences committed by state officials; countering terrorism; incitement to hatred; crimes against humanity and peace, including war crimes; illegal handling and trafficking of firearms, ammunition, explosives, radioactive material or other strategic materials; and the protection of state secrets.

Communists were supported by the Soviet Union, who had publicly accepted the principles not recognizing the parliamentary order, seeing terrorism as a legitimate activity.

Until June 18, 1993, the Estonian Internal Security Service was a department of the central police structure; then, it was reorganised as a distinct entity.

"[3] Criticism of the Estonian Internal Security Service has been presented by Risto Teinonen, a Finnish lawyer and neo-Nazi living in Tallinn.

In 2009, Teinonen launched criminal proceedings against the Estonian Internal Security Service in a Tallinn court, accusing the organization of the politically motivated persecution of innocent people.