Navigating EU-USA Cross-Border Evidence Collection

Key points

• Identify the direction first. Evidence from Europe for a US case and evidence from the US for a European case use different tools.
• The United States and the Czech Republic are both parties to the Hague Evidence, Service and Apostille Conventions.
• US courts are not required to use the Hague Evidence Convention first when discovery is sought from a party within their jurisdiction, but they must consider international comity.
• 28 U.S.C. § 1782 can support European court proceedings, though not private commercial arbitration, and relief is discretionary.
• Sending personal data from the EU to the US needs both a GDPR legal basis and a valid transfer ground. A US order alone is not enough.
• A licensed private investigator can help with lawful fact finding on the Czech side, but has no power to compel testimony or documents.

Start with the direction of travel

The first practical question is not which investigator to call. It is where the proceedings are, where the evidence sits and who holds it. Material moving from the Czech Republic into a US lawsuit raises one set of issues. Material moving from the United States into a Czech or other European proceeding raises another. Criminal matters follow separate state to state channels altogether.

Getting this right early saves time later. It tells you whether you need a letter of request, a US court application, a data transfer assessment or simply lawful research into public records. Many matters need more than one of these, running in parallel.

Taking evidence in the Czech Republic for US proceedings

The 1970 Hague Evidence Convention is the main treaty route. Both the United States and the Czech Republic are Contracting Parties. Under Chapter I, a US court can send a letter of request to the Czech Central Authority, which passes it to a competent Czech court for execution. Chapter II allows evidence to be taken by diplomatic or consular officers and commissioners, subject to the declarations each state has made.

Czech declarations are worth reading before you draft. The HCCH status records declarations inherited from Czechoslovakia under Articles 16, 18 and 40, which concern evidence taking by consular officers and commissioners, and requests for compulsory assistance. Notably, HCCH records no Czech declaration under Article 23, the provision many states use to refuse letters of request for pre-trial discovery of documents. That does not guarantee a broad document request will be executed. A focused request that identifies specific documents and explains their relevance is still the safer course.

US counsel should also remember the Supreme Court’s decision in Société Nationale Industrielle Aérospatiale v. U.S. District Court (1987). The Court held that the Hague Evidence Convention is neither the exclusive nor a mandatory first resort when discovery is sought from a foreign party already subject to a US court’s jurisdiction. Courts must weigh international comity case by case. In practice, a Czech party may face ordinary US discovery requests, while still being bound by GDPR and Czech law when it responds.

Federal Rule of Civil Procedure 28(b) sets out how depositions may be taken in a foreign country, including under an applicable treaty, by letter of request or before a person authorised to administer oaths. It does not override restrictions under local law. Service of process goes through the Hague Service Convention, and public documents can usually be authenticated with an apostille, as both countries are parties to the 1961 Apostille Convention.

Obtaining evidence in the United States for European proceedings

Section 1782 of Title 28 of the US Code lets a federal district court order a person who resides or is found in its district to give testimony or produce documents for use in a proceeding before a foreign or international tribunal. The application can come from the tribunal itself or from any interested person. Privileges still apply.

Meeting the statutory conditions does not make relief automatic. In Intel Corp. v. Advanced Micro Devices (2004), the Supreme Court identified discretionary factors. Courts consider whether the person holding the evidence is a participant in the foreign case, the nature of the foreign tribunal and its receptivity to US assistance, whether the request tries to get around foreign proof gathering restrictions, and whether it is unduly intrusive or burdensome.

Arbitration practitioners need to note ZF Automotive US, Inc. v. Luxshare, Ltd. (2022). The Supreme Court held that Section 1782 reaches only governmental or intergovernmental adjudicative bodies. Private commercial arbitration panels do not qualify, and neither did the ad hoc treaty panel in the companion case. A Prague seated commercial arbitration should not plan its US evidence strategy around Section 1782.

Within the EU, Regulation (EU) 2020/1783 governs the taking of evidence between participating Member States in civil and commercial matters. It is an intra-EU instrument and does not apply to requests to or from the United States.

Criminal matters and electronic evidence

When evidence is needed for a criminal investigation or prosecution, the main transatlantic channel is the Agreement on Mutual Legal Assistance between the European Union and the United States, signed in 2003 and in force since 1 February 2010, alongside bilateral treaties. These are tools for public authorities. They are not a route for private civil discovery.

The US CLOUD Act of 2018 clarified that covered service providers must disclose data in their possession, custody or control in response to qualifying US legal process regardless of where the data is stored. It also allows executive agreements that ease cross-border access to electronic evidence for serious crime. The latest European Commission information describes negotiations on an EU-US agreement on electronic evidence as ongoing rather than concluded.

Inside the EU, Regulation (EU) 2023/1543 has applied since 18 August 2026. It creates European Production and Preservation Orders that judicial authorities can address to service providers in criminal proceedings. Neither instrument gives private parties or investigators any power to obtain communications data.

Moving personal data from the EU to the US

Evidence almost always contains personal data: names in emails, employee records, witness details, photographs. Under Chapter V of the GDPR, any transfer to the United States must rest on a valid transfer ground, and the processing itself still needs a legal basis under Article 6. Both questions must be answered.

The EU-US Data Privacy Framework adequacy decision, adopted on 10 July 2023, covers transfers only to US organisations listed on the Data Privacy Framework List. It does not cover US recipients generally, so check whether the specific law firm, vendor or party receiving the data is certified. On 3 September 2025 the EU General Court dismissed a challenge to the decision in Latombe v Commission (T-553/23). An appeal was lodged as case C-703/25 P, so check the current position before relying on the framework for a sensitive matter.

Where there is no adequacy coverage, standard contractual clauses or other Article 46 safeguards may be available. Article 49(1)(e) allows a transfer where it is necessary for the establishment, exercise or defence of legal claims, but the EDPB treats derogations as exceptional and reads necessity strictly. A link to litigation is not enough on its own.

Article 48 deals with foreign court and authority orders. A US judgment or order requiring disclosure can be recognised or enforced only if it is based on an international agreement such as a mutual legal assistance treaty, without prejudice to the other Chapter V grounds. The EDPB’s Guidelines 02/2024 confirm that a foreign order is not in itself a legal basis. In practice, this pushes towards narrow requests, review and redaction in Europe, staged production and protective orders, rather than a wholesale export of mailboxes.

Where a cross-border EU private investigator fits

In the Czech Republic, private detective services (služby soukromých detektivů) are a concession trade under Act No. 455/1991 Coll., the Trade Licensing Act. A licensed investigator can carry out lawful fact finding that supports counsel’s formal steps. Typical work includes retrieving public register, insolvency and court records, locating witnesses and counterparties, verifying addresses before service, preserving open source material with documented capture details, and lawful observation where it is proportionate and permitted.

Czech procedure is relatively open about what may be put forward. Section 125 of the Civil Procedure Code allows any means capable of establishing the facts to serve as evidence, and Section 89(2) of the Criminal Procedure Code takes a similar approach in criminal cases. Openness is not a guarantee. A court will still assess how the material was obtained, and evidence gathered in breach of privacy or data protection rules can be challenged or disregarded.

It is just as important to be clear about the limits. An investigator cannot compel anyone to give testimony or produce documents, cannot access bank or telecommunications records, and cannot take evidence on behalf of a court. Those steps belong to the formal routes described above. On the US side, investigative tasks should be handled by appropriately licensed US professionals working with US counsel. Exero Group’s role is the Czech and wider EU side of the matter.

A working checklist for counsel

1. Map the forum, the location of each item of evidence and who controls it.
2. Choose the route for each item: Hague letter of request, US discovery, Section 1782, mutual legal assistance or lawful public research.
3. Read the Czech Hague declarations and draft requests that identify specific documents and witnesses.
4. Confirm the GDPR legal basis and the Chapter V transfer ground before any personal data leaves the EU.
5. Check whether each US recipient is on the Data Privacy Framework List, and consider safeguards if it is not.
6. Limit what is transferred. Review, filter and redact in Europe where you can.
7. Plan authentication and translation early, including apostilles and certified Czech or English translations.
8. Keep a record of how each item was found, captured and handled so its origin can be explained later.

Common questions

Is the Hague Evidence Convention mandatory for discovery from a Czech party in US litigation?

No. Under Aérospatiale, US courts may allow ordinary discovery from a foreign party within their jurisdiction, although they must consider international comity. The Czech party still has to comply with GDPR and Czech law when it responds.

Can Section 1782 be used to gather US evidence for a Czech court case?

It can, if the person holding the evidence resides or is found in the relevant US district and the evidence is for use before a foreign tribunal such as a Czech court. The US court then decides whether to grant relief using the Intel factors.

Does Section 1782 help in a commercial arbitration seated in Prague?

Generally not. Since ZF Automotive v. Luxshare in 2022, private commercial arbitration panels are not treated as foreign or international tribunals for Section 1782 purposes.

Can personal data be sent to the US simply because a US court ordered it?

No. Article 48 GDPR means a foreign order is not in itself a basis for transfer. You still need an Article 6 legal basis and a Chapter V transfer ground, such as adequacy, appropriate safeguards or a narrowly applied derogation.

What can a private investigator in the Czech Republic do for a US matter?

A licensed Czech investigator can carry out lawful research and documentation, such as public record retrieval, witness location and open source preservation. They cannot compel evidence or act for a court, so formal evidence taking still runs through the treaty and court routes.