2020), was a case in the United States Court of Appeals for the Fifth Circuit involving the Fourth Amendment implications of Bitcoin transactions.

The evidence against Gratkowski was obtained through a search warrant that was based on information gleaned from an analysis of Bitcoin transactions on the blockchain and customer data from the virtual currency exchange Coinbase.

[4] In 2016, Gratkowski was implicated in a Project Safe Childhood federal investigation involving the receipt of child pornography via a website on the Tor network.

They obtained information about the Bitcoin transactions from the blockchain, which led them to Coinbase, who, after being served with a grand jury subpoena, identified former U.S. Immigration and Customs Enforcement Homeland Security Investigations agent Richard Nikolai Gratkowski as the source of the funds.

The district court denied the motion, ruling that there is no reasonable expectation of privacy in Bitcoin transaction records.