About GCI
Greenberg Corporate Intelligence LLC (GCI) is a Washington, DC-based boutique investigations firm that began operations in March 2023.
GCI’s mission is to provide outstanding research and intelligence services for private-sector clients.
GCI is licensed as a Private Detective Business with the District of Columbia (license no.: PDB40000020).
Team with Broad Industry Experience
Dan Greenberg - President & Founder
Dan Greenberg is GCI’s founder, president, and lead investigator.
Dan has been working in due diligence and corporate investigations since 2010. Dan has a track record of uncovering hard-to-find facts, overcoming difficult challenges, and providing responsive service. His experience has mainly centered on investigative due diligence, shareholder activism support, litigation support, and competitive intelligence.
Dan is licensed as a Private Detective in the District of Columbia (license no. PD40000079).
Languages: English, Hebrew, Spanish
George Shamiyeh - Partner
George joined GCI as a Partner in January 2025. He has a decade of experience in corporate intelligence and investigations, having supported dozens of corporations, investors, and law firms in navigating mergers and acquisitions, capital markets transactions, corporate contests, and market entry strategies.
Before joining GCI, George was a senior manager for Visa’s Integrity Risk Program, where he led research efforts focused on identifying and mitigating fraud, abuse, and illegal activity within the payment ecosystem. He joined Visa after five years at Forward Risk, where he managed numerous global investigations in support of corporate contests, geopolitical risk advisory matters, and investment due diligence. George began his career at global risk management and compliance solutions company Exiger, where he led enhanced due diligence investigations for Fortune 500 corporations and their legal counsel, supporting hundreds of equity capital markets transactions, providing clients with actionable intelligence to mitigate risks.
Languages: English, Arabic
Claire Vinocur - Partner
Claire joined GCI as a Partner in January 2025. She has over a decade of experience in political opposition research and corporate intelligence, from state and federal campaigns to investigative due diligence and litigation support.
Claire began her career at the Democratic National Committee, where she conducted opposition research across two presidential campaign cycles and served as a member of the Biden-Harris Transition team. From 2021 to 2024, she worked as an associate director for a DC-based investigations and intelligence firm, where she focused on investigative due diligence and public policy matters. In early 2024, she returned to the DNC to manage opposition research for the committee’s first-ever team focused on countering third-party and independent presidential candidates.
Claire holds a B.A. in political science from Carleton College and a master’s in public policy from Harvard Kennedy School.
Claire is licensed as a Private Detective in the District of Columbia (license no. PD40000166).
Languages: English
Krystal L. Ramírez - Vice President
Krystal joined GCI in July 2023 as Vice President. Krystal has extensive experience in the corporate intelligence services industry, having held leadership roles at various firms in the DC area prior to GCI.
Previously, Krystal worked in politics, conducting opposition research at the Democratic National Committee and prospect research at the League of Conservation Voters. Krystal began her career at KTRK-TV in Houston, TX.
Krystal is licensed as a Private Detective in the District of Columbia (license no. PD40000089).
Languages: English, Spanish
Diane Francoulon - Director
Diane joined GCI in January 2024 as a Director. Diane began her career in the due diligence industry before joining a boutique investigations and intelligence firm. Most recently, Diane worked as an OSINT analyst for a cryptocurrency exchange.
She holds a B.A. in Political Science and a B.A. in French and Francophone Studies from the University of Florida and an M.A. in International Affairs from American University.
Diane is licensed as a Private Detective in the District of Columbia (license no. PD40000110).
Languages: English, French
Sarah McKellar - Senior Associate
Sarah joined GCI in September 2023 as a Senior Associate. She began her career in the due diligence and corporate investigations industry before working in the Office of the Chief Privacy Officer at the Federal Trade Commission, where she specialized in privacy, consumer protection, and cybersecurity policy. Her approach to investigations is centered around her intellectual curiosity and a desire to uncover truths through both open-source intelligence and human intelligence.
She holds a B.A. in International Studies from American University, where she focused her studies in national security, foreign policy, and European affairs.
Sarah is licensed as a Private Detective in the District of Columbia (license no. PD40000091).
Languages: English
Elise Blackburn - Senior Associate
Elise joined GCI in March 2024 as a Senior Associate. She most recently worked as a Senior Associate for a due diligence and investigations firm and as an OSINT analyst for a geopolitical risk start-up. Previously, Elise completed a fellowship at the Trust Accountability and Inclusion Collaborative and interned at the Coalition for the International Criminal Court.
She holds an MSc in Comparative Politics from the London School of Economics and Political Science and BAs in Law and Political Science from the Dual BA Program between Sciences Po Paris Campus de Reims and Columbia University.
Elise is licensed as a Private Detective in the District of Columbia (license no. PD40000119).
Languages: English, French, Spanish