Politiets Efterretningstjeneste (PET) (Danish Security Intelligence Service abbreviated DSIS) is the national security intelligence agency of Denmark. The agency focus solely upon domestic security while foreign intelligence operations is handled by Forsvarets Efterretningstjeneste – an intelligence branch under the Danish military.
The stated overall purpose of PET is to "prevent, investigate and counter operations and activities that pose or may pose a threat to the preservation of Denmark as a free, democratic and safe country."
Counter terrorism does not only encompass stopping terrorist attacks upon Denmark and Danish interests but also to ensure Denmark isn’t used as a base of operations for carrying out terrorist attacks in and against other countries. Furthermore PET attempt to gather evidence to ensure that terrorists are prosecuted. Denmark is obliged by UN and EU resolutions to support other states in prosecuting terrorists.
Aside from the three main areas PET also provides counselling to Danish companies on how to avoid espionage(but is only directly involved in countering industrial espionage if an agency of a foreign government is involved). It has a role as national security advisor to the Danish government, public authorities and other branches of the police along with a number of other activities common to domestic security organisations.
PET is a part of the Danish police but refers directly to the Minister of Justice.
The headquarter is located in Copenhagen, and they have offices in Århus and Odense located in the local police stations. Because the service is integrated with the Danish police, they have representatives in all police precincts of Denmark. 
Several organs oversee PET in order to make sure the agency does not misuse its powers.
Besides those listed the agency is also under the control of the Courts of Denmark (which has to approve many special steps of investigation, e.g. wire-tapping.)
PET was criticised in the late 1990’s for being closed to the public and has tried to counter these claims by adopting a more open approach. Thus PET has taken to maintain a website explaining its overall aims and obligations and publishing an annual public report surveying extremist activities in Denmark and the threat level to national domestic security (albeit only in a very overall fashion).
PET does not comment on whom they offer specific bodyguard protection. However, it is publicly established that the following people are under permanent protection: