Her Majesty Queen Jadis' Secret Police also known as the White Witch's Secret Police was the undercover police force established by the Narnian ruler Jadis.
This Police force was created specifically for the purposes of intimidation, reconaissance, and spying on the oppressed Narnian citizens. They also went so far as to arrest any who they viewed of as traitors, including the Faun Tumnus, or those they were ordered to by Jadis.
Most of the Secret Police was made up of wolves, including Maugrim, the head Captain of the Police, Maugrim, but it also included some of the ever-listening trees and various other creatures, who worked as spies.
Maugrim was killed during the Skirmish at the Stone Table, thereby the Secret Police lost its captain, and it dissolved after the White Witch died at the First Battle of Beruna, and the Pevensies were all crowned the new monarchs of Narnia.