
The Department for Protecting the Public Security and Order (Отдѣленіе по Охраненію Общественной Безопасности и Порядка), usually called `guard department` (okhrannoye otdelenie) and commonly abbreviated in modern sources as Okhrana or Okhranka in Russia, was a secret police force of the Russia.....
Found on
http://en.wikipedia.org/wiki/Okhrana

The security police under Alexander III (1881-94). Covert operations (using nonuniformed agents and informers) were used to uncover and collect evidence against revolutionary groups.
Found on
http://soviethistory.msu.edu/glossary/

The Okhrana was the Tsarist Russian security and intelligence agency from 1881 to 1917. After the Bolshevik revolution, the Cheka modelled itself on the Okhrana which had successfully used penetration agents and agents provocateurs.
Found on
http://www.probertencyclopaedia.com/browse/FO.HTM

The security police under Alexander III (1881-94). Covert operations (using nonuniformed agents and informers) were used to uncover and collect evidence against revolutionary groups.
Found on
https://irp.fas.org/world/russia/su_glos.html
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