Users of Canadian cryptocurrency exchange QuadrigaCX are unable to access most of their funds, according to CoinDesk, for an unfortunate reason: the exchange’s founder, Gerald Cotten, recently died, and was the only person who knew a vital password.

QuadrigaCX’s website recently went down and the company filed for creditor protection, saying that it was trying to address some “liquidity issues.” In court filings, Cotten’s wife says that the company owes its users $250 million CAD ($190 million USD), and that to protect its users funds from hackers, a portion of its users coins were kept in a “cold wallet” — a physical device that isn’t connected to the internet. Cotten was the only person with access to the device, according his wife, and she doesn’t have the password to decrypt it. The company also had several banking and payment processor issues, with some other organizations holding QuadrigaCX’s funds.

Users have been skeptical of the exchange’s claims, with some experts noting that some of its wallets have seen some activity since its issues were publicized. However, if the company has indeed placed its cryptocurrency in a now-inaccessible device, it seems likely that thousands of users will never be able to recover their funds.