Background: First Systematic Disclosure of Police Crypto Forensics Methodologies
According to a report by the South China Morning Post, a technical paper authored by Sun Shengbin of Wenzhou Public Security Bureau and Lou Yandi of Zhejiang Provincial Public Security Department's Criminal Investigation Corps was published on June 4, 2026, in the peer-reviewed journal Criminal Technology. This marks the first time Chinese law enforcement has publicly disclosed the full toolkit and procedural framework used to investigate crimes involving Bitcoin, Ethereum, and other digital assets. The paper spans the entire lifecycle of a crypto-related investigation: physical device cracking, electronic evidence collection, on-chain transaction tracing, and asset freezing or seizure.
Device Forensic: Private Keys and Mnemonics Are the Easiest Entry Point
The paper highlights that many users store their recovery phrases or private keys in unencrypted locations such as smartphone notes, WeChat messages, or plain-text files on computers. Upon seizing a suspect's device, investigators immediately conduct an exhaustive search for any trace of private keys or mnemonics. This technique exploits a common security oversight among crypto holders: even when using cold storage or hardware wallets, any digital footprint left on a connected device provides law enforcement with a direct path to the assets.
On-Chain Tracing: Transaction Fee Patterns and Exchange KYC as Key Breakthroughs
On the blockchain side, the paper describes several tracing methodologies. One highlighted method involves tracking the transaction fees paid to miners, linking them to known exchange deposit addresses (e.g., Binance, OKX, and HTX). After identifying the suspect's transactions, police can obtain Know-Your-Customer (KYC) records from these centralized exchanges through formal legal channels. This implies that even if a criminal uses mixing services or privacy coins, the eventual fiat off-ramp at a regulated exchange creates a vulnerability that law enforcement can exploit via traditional judicial cooperation.
Asset Freezing and Seizure: Six-Month Freeze with Renewal Option
The paper clarifies that for funds held on exchanges, police can freeze the suspect's account for up to six months, with the possibility of renewal upon legal approval. This aligns with the asset seizure timelines stipulated in China's Criminal Procedure Law. Critically, the document lays out strict operational safeguards: investigators must not personally hold private keys; they must adhere to the principle of 'case handling and asset custody separation'; and a transparent chain-of-custody record must be maintained to prevent corruption or evidence tampering.
Industry Implications: Tighter Regulatory Grip on Crypto Anonymity
The publication of this technical paper signals that Chinese law enforcement has developed a standardized and professionalized approach to cryptocurrency investigations. For traders and holders, storing private keys on internet-connected devices is no longer a safe practice. For exchanges, cooperation with judicial inquiries has become a non-negotiable compliance requirement. As on-chain forensic tools and legal frameworks continue to mature, the practical anonymity of cryptocurrencies will face increasing challenges from government oversight.