The European Union Agency for Law Enforcement Cooperation, better known as Europol, formerly the European Police Office and Europol`s Narcotics Office, is the European Union(EU) law enforcement agency set up in 1998 to deal with criminal investigations and combat major international organised crime and terrorism through cooperation between the competent authorities of EU Member States. The Agency has no executive power and its officials do not have the right to arrest or act on suspects without the prior authorisation of the competent authorities of the Member States. In 2016, based in The Hague, 1,065 people were employed. Europol has its origins in TREVI, a forum for security cooperation created in 1976 between the European Community`s interior and justice ministers. Initially, TREVI focused on international terrorism, but quickly began to cover other areas of cross-border crime within the Community. At the European Summit in Luxembourg on 28-29 June 1991, Chancellor Helmut Kohl called for the creation of a European police authority similar to the Federal Bureau of Investigation (FBI), sowing the seeds of police cooperation throughout Europe. At the summit, the European Council agreed to “create a European Judicial Police Station (Europol) by 31 December 1993.      Denmark was not allowed to participate in the overhaul of the 2016 Europol Regulation because of its diversion from the area of freedom, security and justice. In a referendum in December 2015, she opposed the transformation of her opt-out into a case-by-case opt-in, which would have allowed her to participate in the new regulation and remain a member of Europol.
However, Denmark and the European Union agreed on a cooperation agreement in December 2016. The agreement was adopted by the European Parliament and the Danish Parliament on 27 April 2017 and signed on 29 April 2017, two days before Denmark was cut off from the Agency.    Europol also cooperates closely with a number of EU institutions and agencies on the basis of cooperation agreements. […] Member States consider the following areas to be issues of common interest: […] police cooperation to prevent and combat terrorism, drug trafficking and other serious forms of international crime, including, where appropriate, certain aspects of customs cooperation, as part of the establishment of an EU-wide information exchange system within a European Police Office (Europol).  This network of liaison officers communicates via the SIENA system, a state-of-the-art tool that enables rapid, safe and user-friendly communication, as well as the exchange of operational and strategic information and information on crimes between Europol, Member States and third parties that have concluded cooperation agreements with Europol.