Mr Berk started his career with German Customs Investigation Service in 1985. For more than ten years, he dealt with counter proliferation issues in the field of export controls. His main tasks were the support to criminal investigations as well as international cooperation, in particular in the framework of the Missile Technology Control Regime (MTCR).

When he switched over to the anti-narcotics department of German Customs Investigation Service, the international cooperation aspect was again a priority of his tasks followed by an appointment in 2008 as a Customs Liaison Officer to the United Arab Emirates, supporting all kinds of customs cooperation with third countries.

Back in Germany, Mr Berk then served in the field of operational assistance to criminal investigations as Head of department of German Customs Special Weapons and Tactics Team (SWAT) as well as Head of department for undercover agents, informant handlers and witness protection.

Before joining Europol, he was Head of department of international customs cooperation. This covered 20 Customs Liaison Officers abroad, the central authority for mutual assistance in customs matters, the cooperation with EUROPOL and INTERPOL, the Police Customs Cooperation Centres (PCCCs) as well as customs-related cooperation platforms i.e. the EU Council (Law Enforcement Working Party Customs LEWP-C), the World Customs Organization WCO (Enforcement Committee), the Baltic Sea Task Force (BSTF) and some more.

Since May 2020, Mr Berk is Head of unit for Expertise and Stakeholder management (ESM) in the recently established European Financial and Economic Crime Centre (EFECC) of Europol. Main aspects here are strategic cooperation with stakeholders on national as well as European level such as FIUs, Customs/Tax authorities, DG FISMA, DG TAXUD, EPPO, EUROJUST and the private sector in the framework of the EFIPPP (Europol Financial Intelligence Public Private Partnership) just to name a few.