The Security Police (Suojelupoliisi--SUPO) had its headquarters in Helsinki, but it maintained bureau and district offices in various parts of Finland. Formed in 1948, it replaced a similar police force dating from the late 1930s. Its function was to investigate crimes and offenses against the law and order of the state, including subversion, conspiracy, and espionage. SUPO had, in addition, certain responsibilities for safeguarding classified government documents and for checking on foreign citizens visiting or working in Finland. It conducted liaison with security and intelligence organizations of other countries. Agents of SUPO did not have the right to make arrests or to detain anyone, nor were they authorized to search private residences. Anyone suspected by SUPO of having committed a crime was dealt with by a criminal investigation unit.

The country faced few internal security problems. It continued to be a homogeneous nation with only 20,000 foreign residents and an immigration quota of 200 people a year. Admittance was denied to job seekers from Third World countries. The few Soviet defectors who managed to escape across the border into Finland were carefully screened, and most were sent back. A few were granted asylum as political refugees others succeeded in reaching Sweden before being apprehended by Finnish authorities.

Data as of December 1988