A Miami man faces multiple felony charges after police say he stole nearly $2 million worth of Bitcoin from a former employer — a theft that went undetected for years while the cryptocurrency sat locked in a safe.
Nahum Reynaldo Castro, 40, was arrested Tuesday on charges of grand theft, money laundering, unlawful use of a communications device, and offenses against computer users, according to an arrest report obtained by NBC 6.
The case stretches back to December 2017, when the victim began purchasing Bitcoin as a long-term investment. He bought a hardware wallet to store the digital currency, and turned to Castro — a trusted employee since 2013 and an IT specialist — to handle the wallet’s setup and security, the report said.
By the end of January 2018, Castro had secured more than $217,000 worth of Bitcoin on behalf of his employer. The hardware wallet was then locked in a safe inside the victim’s home, where it remained untouched for years.
That changed in July 2025. While in the middle of a move, the victim opened the safe and accessed the wallet — only to find it empty. The Bitcoin was gone. At the time of the discovery, the stolen holdings had grown to a value of more than $1.9 million, according to the arrest report.
Investigators determined the theft had taken place in 2020, more than five years before the victim realized anything was missing. Castro continued working for the victim until 2024, the report said.
The wallets seed phrase gave away Castro
Central to the investigation was the wallet’s seed phrase — a master recovery key that grants full access to a cryptocurrency wallet. According to the report, only two people had knowledge of that phrase: the victim and Castro.
Bank records proved critical in building the case. Deposits into Castro’s accounts aligned with withdrawals from the Bitcoin wallet, providing investigators with the financial corroboration needed to connect him to the theft, NBC 6 reported.
The case highlights a risk in the cryptocurrency space that security experts have long flagged: placing complete trust in a single person during the setup of a digital asset wallet.
Because Bitcoin transactions are recorded on a public blockchain but are not reversible, stolen funds are nearly impossible to recover without law enforcement intervention.
Castro was booked into jail following his arrest and was set to appear in bond court Wednesday. He has not entered a formal plea in the case.
