After 18 days of testimony and deliberation, a Manhattan federal court has declared a mistrial in the U.S. v. Peraire-Bueno case, one of the most closely watched crypto trials in recent years. Judge Jessica G.L. Clarke announced the outcome late Friday after the jury failed to reach a unanimous verdict on wire fraud and money laundering charges against two brothers accused of exploiting Ethereum’s transaction system for $25 million.
The defendants, Benjamin and Noah Peraire-Bueno—both MIT-educated—were accused of manipulating Ethereum’s Maximal Extractable Value (MEV) mechanism, which determines how transactions are ordered within blocks. Prosecutors alleged that the brothers conducted “sandwich attacks,” a strategy that places two of their own trades around another user’s pending transaction to profit from price changes. The prosecution characterized this as a deliberate scheme that disguised theft under the appearance of technical sophistication.
Defense attorneys maintained that the pair operated within Ethereum’s open and transparent blockchain rules, arguing that their actions merely leveraged publicly available code. They said the alleged exploit was not a criminal act but an example of interacting with a decentralized system as designed. According to courtroom transcripts cited by Inner-City Press journalist Matthew Russell Lee, defense lawyer Looby stated that “the government didn’t want this description of intent in there,” highlighting disagreement over how to define criminal intent in decentralized finance (DeFi).
Jurors deliberated for three days but could not agree on whether the defendants acted with criminal intent, or mens rea. The prosecution asserted the brothers acted with a “wrongful purpose,” while the defense said they believed their conduct was consistent with blockchain norms. Judge Clarke noted during proceedings that “there is no requirement that the defendants knew their actions were illegal” under existing federal statutes, underscoring the legal ambiguity surrounding DeFi-related cases.
Observers described the proceedings as a test of whether algorithmic trading behavior on decentralized systems could amount to fraud under conventional law. The mistrial leaves open questions about how regulators and courts will treat similar cases in the future. The Department of Justice has not yet announced whether it plans to retry the case.
The trial drew comparisons to the Tornado Cash litigation, which also involved debates over decentralization and legal accountability. In that case, a U.S. federal appeals court struck down sanctions imposed by the Treasury Department on Tornado Cash, another event that spotlighted the tension between blockchain autonomy and federal oversight.
The Peraire-Bueno mistrial, like Tornado Cash, illustrates how defining intent and liability in decentralized networks continues to challenge traditional interpretations of criminal conduct.
Featured image credits: Freepik
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