Research On Forensic Admissibility Of Blockchain Transaction Trails In Courts

06 Oct 2025 --
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1. United States v. Gratkowski (5th Cir., U.S., 2020)

Facts:
In this case the defendant was charged in the U.S. for receipt of child‑pornography via websites and payment in Bitcoin. Investigators used blockchain transaction data to identify transfers and to link wallet addresses to an exchange (Coinbase) account. The government obtained a subpoena to Coinbase, identified the user, and traced transaction trails on the blockchain.
Blockchain‑trail forensic issues:

The court addressed whether the blockchain transaction records (public ledger + data from the exchange) were subject to the Fourth Amendment (search & seizure) protections. The Fifth Circuit compared them to bank records and held that because the user voluntarily revealed transaction information to the blockchain network and to the exchange (a third‑party), the user had no reasonable expectation of privacy.

The blockchain trail served as part of the evidentiary chain to link the defendant to the payments and to illicit material.
Court’s holding and admissibility issues:

The court held that the subpoena‑derived records were admissible; the blockchain data and exchange records were not protected by Fourth Amendment.

The case implicitly treated blockchain transaction trails as reliable forensic sources when combined with third‑party account data.
Take‑aways:

Blockchain trails can be admissible evidence in U.S. federal criminal proceedings if properly linked to a person via third‑party exchange records.

Key forensic concerns: linking an anonymous wallet to a real person; ensuring chain of custody and reliability of third‑party records.

Because the court accepted the blockchain data and exchange logs, this case supports admissibility of blockchain transaction trails in criminal prosecutions under U.S. law.

2. AA v Persons Unknown (England & Wales, 2019/2020)

Facts:
An insurance company paid a ransom in Bitcoin after its client was hacked. The insurer traced some of the Bitcoin payments through the blockchain to a wallet linked to a cryptocurrency exchange. The plaintiff applied for a proprietary injunction (and freezing order) against “Persons Unknown” to preserve the Bitcoins.
Blockchain‑trail forensic issues:

The court had to determine whether cryptoassets (Bitcoin) were “property” under English law (which affects remedies).

The tracing of bitcoins on the blockchain was central: logs from the blockchain showed 109.25 BTC paid, 96 BTC traced to a wallet at Bitfinex exchange, 13.25 BTC untraceable fiat‑conversion. Forensic investigators used blockchain analytics to demonstrate the flow of funds.
Court’s holding and admissibility issues:

The court held that cryptoassets are indeed property (able to be subject to proprietary injunctions).

The blockchain‑based forensic trail was accepted as sufficient for interim relief (injunction), because it showed definable and identifiable assets.

The judge commented that although cryptoassets don’t fit neatly into old categories of property (chose in possession vs chose in action), they satisfy criteria (definable, identifiable, transferable, permanence) for property.
Take‑aways:

Blockchain transaction trails, when properly documented, can form the basis of civil relief (proprietary claims, freezing orders) in the UK.

For admissibility, linking the trail to real wallets/exchanges is critical; expert forensic report aided the tracing.

This case is a foundational precedent for blockchain/evidence in civil contexts.

3. Mooij v Persons Unknown (England & Wales, 2024)

Facts:
A claimant sought summary judgment for recovery of Bitcoin and cash allegedly obtained by fraud via a fake trading platform. The defendant wallets were described as “Persons Unknown” and the claimant traced the Bitcoin to wallets controlled by named exchange defendants. Forensic blockchain analysis was used to trace ~20.34 BTC and €330,000 cash.
Blockchain‑trail forensic issues:

The forensic analysis traced transactions on the blockchain, wallet addresses, timing, intermediary exchanges (Huobi etc). The claimant provided expert evidence documenting the tracing.

Alternative service of proceedings (via NFT airdrop, etc) was accepted given anonymity of defendants.
Court’s holding and admissibility issues:

The court granted summary judgment for delivery up of the traced Bitcoin and a money judgment for the cash.

The court accepted blockchain transaction trails as valid evidence of wrongdoing, wallet control and tracing.

The freezing injunction was continued post‑judgment, and the claimant was excused from providing a cross‑undertaking in damages.
Take‑aways:

Blockchain‑trail evidence can support final relief (not just interim) when forensic analysis is robust.

Demonstrates courts are increasingly comfortable with blockchain transaction evidence in civil fraud matters.

Emphasises importance of expert forensic reports, linking wallet addresses to exchanges and persons.

4. Toma v Murray (England & Wales, 2020)

Facts:
An individual sought an injunction over Bitcoin assets held in a brokerage account. The claim was based on alleged misappropriation of the Bitcoin by the defendant. The claimant sought freezing/proprietary orders.
Blockchain‑trail forensic issues:

The claimant presented forensic blockchain traces of Bitcoins held in the account and sought that the assets be subject to proprietary relief.
Court’s holding and admissibility issues:

The court declined to continue a proprietary injunction over the Bitcoin assets. The judge expressed concern about the volatility of Bitcoin: that by the time of liquidation, the claimants or defendants might suffer significant losses, making the injunction an inadequate remedy.

The court did not reject blockchain‑trail evidence per se, but highlighted practical issues such as volatility and equitable fairness in granting relief.
Take‑aways:

Even when blockchain transaction evidence is present, courts may deny relief because of other factors (volatility of crypto, complexity of asset freeze).

The case shows admissibility is not enough; substantive and procedural fairness matter.

For forensic use, one must consider remedial practicality, timing of relief, and potential harms to third parties.

Additional Considerations & Emerging Challenges

From the case law and forensic practice, several key points emerge regarding admissibility of blockchain transaction trails:

a) Authentication & Integrity:
Courts require proof that the blockchain transaction record is what it purports to be: wallet addresses, hash values, timestamps, chain confirmations. For example, in many jurisdictions the requirements for electronically stored evidence include showing chain of custody, no tampering, correct extraction. The immutable nature of blockchain aids this, but parties still must show how the trail was obtained, link from wallet to party, and that no intervening manipulation occurred.

b) Linking Wallets / Aliases to Real Persons:
A blockchain trail by itself is just a public ledger of anonymous addresses. For admissibility and weight, parties must link the addresses to identifiable persons or entities (e.g., via exchange logs, KYC records, forensic expert analysis). In the UK cases above, wallet addresses linked to known exchanges and persons unknown seemed sufficient for interim relief. In criminal cases, identity linkage is more critical for conviction.

c) Jurisdiction & Asset Location:
Blockchain transactions often span multiple jurisdictions. Courts will ask: where is the asset located (lex situs), where is the defendant domiciled, where did the transaction occur, which law applies? For example the UK cases accepted jurisdiction because the claimant was domiciled in England and entered bank transfers from England into Bitcoin chain. Transaction trails may show cross‑border flows and multiple nodes.

d) Expert Witness & Technical Explanation:
Because blockchain is technical, courts often rely on expert witness testimony to explain how the ledger works, how transactions are traced, how wallet clustering/analytics identify flows. The forensic report’s quality and methods (chain‑analysis, link to exchanges) affect admissibility and weight.

e) Remedy vs Evidence:
Admissibility of blockchain trails is one thing; the remedy (injunction, freezing, delivery up) is another. As seen in Toma v Murray, even if the blockchain evidence is accepted, the court may deny relief due to asset volatility or inequitable consequences.

f) Legal Uncertainty & Emerging Standards:
Blockchain evidence is still a relatively new field; different jurisdictions vary in their approach. Some jurisdictions may require special certificates (e.g., India’s Section 65B for electronic records) or face technical/interpretive hurdles. The admissibility of blockchain‑based logs may be questioned on chain‑of‑custody, mutability, expertise, comprehension by judges.

Summary Table

Case	Jurisdiction	Nature of Blockchain Evidence	Key Forensic Issues	Legal Outcome
United States v. Gratkowski	U.S. (5th Cir.)	Bitcoin transaction trace + exchange records	Linking wallet to person; third‑party doctrine	Evidence admitted; conviction upheld
AA v Persons Unknown	England & Wales	Bitcoin ransom payment & tracing to exchange	Wallet tracing; proprietary claim	Cryptoassets held property; injunction granted
Mooij v Persons Unknown	England & Wales	Blockchain trace of Bitcoin/cash fraud	Expert trace; wallet‑exchange link	Summary judgment & delivery of BTC granted
Toma v Murray	England & Wales	Trace of Bitcoin assets	Asset volatility; suitability of remedy	Proprietary injunction refused (though evidence accepted)

Implications for Forensic Practitioners & Legal Teams

When using blockchain transaction trails as forensic evidence, ensure the linkage of addresses → entities/persons is well documented and explained.

Maintain chain of custody, hash values, timestamps, original logs, and expert reports to show integrity of the trail.

Prepare for challenges about jurisdiction, asset location, and technical comprehension of blockchain by judges.

Understand that admissibility is only part of the battle—courts will consider whether relief is appropriate (freezing assets, injunctions) given the nature of cryptoassets.

Be aware of evolving standards in differing jurisdictions; what is accepted in the UK (civil/proprietary relief) may differ in criminal domains or other countries.