A pair of Ohio prison inmates used bitcoin as part of a cybercrime scheme uncovered last year, according to a newly released report.

The 50-page document, released by Ohio’s Office of the Inspector General this week, outlines a plot in which the two inmates at the Marion Correctional Institution went so far as to maintain two makeshift computers hidden above their cell.

Though details about how they used the digital currency were scarce, a search for clues by state investigators turned up bitcoin wallets on the prison’s computer system, along with other clues indicating an identity fraud plot.

The report explained:

“[I]t appears the Department Offender Tracking System (DOTS) portal was attacked and inmate passes were created. Findings of bitcoin wallets, [Stripe] accounts, bank accounts and credit card accounts point toward possible identity fraud, along with other possible cybercrimes.”

The two inmates were able to effectively hijack the system by using stolen information from a former corrections employee and computers obtained from a hardware salvage program conducted at the prison.

Who’s to blame? Primarily prison staff, according to the report, who were faulted for not reporting the incident and for failing to properly secure the scene after it was discovered.

Representatives for the prison told CBS News that they had since moved to adopt the recommendations suggested in the report.

The full report can be found below:

2015-CA00043 by CoinDesk on Scribd