Bas A.S. van Leeuwen

Attorney and Forensic Auditor

Navigating the maze of legislation, jurisprudence, and legal doctrine, Bas A.S. van Leeuwen (LL.M., Esq.), attorney and forensic auditor, is ready to assist companies and individuals involved in or victimized by crimes, particularly in the realm of financial and economic crime, also known as ‘white-collar crime’. With a keen eye for detail and a deep understanding of complex legal landscapes, Attorney van Leeuwen provides expert assistance in cases such as money laundering, terrorism financing, sanctions and embargoes, fraud and deception, bribery and corruption, tax evasion and tax fraud, market manipulation, collusion and antitrust violations, cybercrime and data breaches, mortgage fraud, credit fraud, insurance fraud, customer fraud, misuse of corporate assets, public procurement fraud, HR fraud, corporate criminal law, insider trading, accounting and financial reporting fraud, misleading business practices, invoice fraud, CEO fraud, and supplier fraud. Focusing on guiding clients through internal investigations, advising, litigating, and negotiating with regulators and the Public Prosecution Service, Attorney van Leeuwen aims to create sustainable value and freely share his extensive knowledge, allowing his clients to look forward with confidence, knowing that every aspect has been carefully considered.

Holistic approach to regulatory, operational, analytical, and strategic challenges

Bas A.S. van Leeuwen (LL.M., Esq.), attorney and forensic auditor, distinguishes himself through his multidisciplinary approach to combating financial and economic crime. His deep expertise and extensive experience enable him to offer a holistic view of complex legal, financial, and forensic issues. Van Leeuwen adopts a holistic approach to regulatory, operational, analytical, and strategic challenges, ensuring that all aspects of a problem are thoroughly and comprehensively addressed.

As an attorney, van Leeuwen combines his thorough knowledge of the legal system with a sharp understanding of business practices and financial mechanisms. He analyzes legal issues from various areas of law, including criminal law, privacy law, IT law, financial law, and compliance, to develop a comprehensive legal strategy that protects his clients and safeguards their interests.

As a forensic auditor, van Leeuwen brings deep knowledge of forensic techniques, financial analysis, and investigative methods. He is adept at analyzing financial data, uncovering hidden patterns, and identifying potential fraud indicators. His expertise extends to conducting detailed forensic investigations, using advanced tools and methodologies to uncover fraudulent activities and gather evidence that holds up in court proceedings.

Through his multidisciplinary approach, van Leeuwen can effectively tackle a wide range of financial and economic crimes, including money laundering, fraud, corruption, market manipulation, tax evasion, and more. He combines his legal and forensic knowledge to not only investigate and address the crimes but also to advise and implement preventive measures to reduce future risks.

Van Leeuwen’s holistic approach also involves close collaboration with other professionals, such as financial experts, forensic accountants, IT specialists, and ethical hackers. By working with experts from various fields, he can provide a comprehensive and integrated approach to identifying, investigating, and addressing complex criminal activities.

In short, Bas A.S. van Leeuwen’s multidisciplinary and holistic approach combines legal expertise, forensic skills, and collaboration with other professionals to offer his clients comprehensive and effective solutions for regulatory, operational, analytical, and strategic challenges in the realm of financial and economic crime.

White Collar Crime Defence & Corporate Investigations

In today’s complex business environment, accusations of financial misconduct, fraud, bribery, money laundering, corruption, or violations of international sanctions can cause significant disruptions to a client’s operations and damage their reputation. Organizations face an increasingly intricate landscape of regulations, operational challenges, analytical requirements, and strategic decisions, particularly in the areas of fraud risk management, financial and economic crimes, and ESG (Environmental, Social, and Governance) considerations.

Within this context, Bas A.S. van Leeuwen (LL.M., Esq.), attorney and forensic auditor, is renowned for his commitment to advising clients and providing solutions for challenges in regulatory compliance, operational optimization, data analysis, and strategic planning related to fraud risk management, financial and economic crimes, and ESG. With his extensive legal expertise and practical approach, he plays a crucial role in guiding organizations through these complex terrains while protecting their interests and helping them achieve their objectives in a rapidly changing and challenging business environment.

Criminal Cases

In the field of criminal cases, Bas A.S. van Leeuwen leverages his in-depth understanding of financial and economic crime to directly tackle challenges. With a keen eye for the nuances of the legal landscape, he adeptly navigates criminal investigations, meticulously analyzes evidence, and develops robust defense strategies. His expertise spans a wide range of financial crimes, including embezzlement, securities fraud, insider trading, and cybercrime. His proactive approach and meticulous attention to detail ensure that clients receive comprehensive legal representation, minimizing risks and protecting their interests throughout the legal process.

Administrative Oversight and Enforcement Cases

When it comes to administrative oversight and enforcement cases, Bas A.S. van Leeuwen brings a wealth of experience and insight. He understands the complexity of regulatory compliance and enforcement actions and provides strategic guidance to withstand regulatory investigations, inquiries, and enforcement procedures. Whether dealing with oversight by regulatory bodies or compliance audits, van Leeuwen’s proactive approach enables clients to effectively address regulatory challenges while minimizing legal exposure and reputational damage. He works tirelessly to ensure that clients meet regulatory requirements by implementing robust compliance programs and risk management frameworks tailored to their specific needs and industry standards.

Internal and External Investigations

In the realm of internal and external investigations, Bas A.S. van Leeuwen is a trusted advisor known for his rigorous approach and unwavering commitment to uncovering the truth. With his extensive legal background and forensic expertise, he conducts thorough investigations into allegations of misconduct, fraud, and regulatory violations. Van Leeuwen meticulously analyzes financial data, interviews key stakeholders, and utilizes advanced forensic techniques to uncover evidence and establish facts. Whether conducting internal investigations to mitigate internal risks or responding to external investigations by regulatory authorities, van Leeuwen ensures that clients are well-prepared to address the findings and implement effective corrective measures. His proactive approach helps clients protect their reputation, restore trust, and emerge stronger from challenging situations.

Professional Registrations and Memberships

  • Dutch Bar Association
  • Bar Association Middle-Netherlands
  • Foundation for the Education of Criminal Law Attorneys Middle-Netherlands
  • Dutch Association for Information Technology and Law
  • Association of Social Advocates Netherlands

Professional Experience

  • Attorney-at-law (2010-present)
  • Forensic Auditor (2006-present)
  • Senior Inspector Forensic Fraud Auditing (2008-2010), Ultrascan Advanced Global Investigations
  • Security Consultant / Investigator (2006-2008), PINKERTON | Corporate Risk Management Services
  • Investigative Analyst / Forensic Auditor (2004-2006), 4iTrust Forensic Services and Investigations
  • Trainee (2003-2004), Police Unit Middle-Netherlands


  • Diploma Professional Training for Lawyers, Professional Training for Lawyers, 2010-2013
  • Master of Laws – LLM, Criminal Law / Criminal Law Education, Utrecht University, 1998-2003


  • The Dutch and Belgian Private Investigation Industry – Influence of the European Community Legal Order, NJB (2006) No. 12, p. 698-701

Register of Legal Areas

  • Main Legal Specialization: Criminal Law, sub-specializations: Financial Economic Criminal Law, Tax Criminal Law, International Criminal Law, Environmental Criminal Law, Extradition Cases;
  • Main Legal Specialization: Information Law, sub-specialization: IT Law
  • Main Legal Specialization: Privacy Law