The alleged thief behind Iceland's "Big Bitcoin Heist" has escaped from prison and escaped to Sweden.

Sindri Thor Stefansson, who is accused of stealing 600 cryptocurrency mining computers across at least four separate incidents between December 2017 and January 2018, allegedly flew to Sweden on a flight with Iceland's prime minister, according to a report from The Guardian published Wednesday.

Police arrested a further 22 individuals as possible accomplices, though it is unclear how many remain in custody.

The heist – which resulted in the theft of an estimated $2 million worth of mining hardware – is the largest in Iceland's history, as previously reported. At the time, officials called it "a highly organized crime" that was coordinated "on a scale unseen before."

As such, Stefansson likely had help escaping, local police chief Gunnar Schram was quoted as saying. He told reporters that the alleged criminal "had an accomplice" to help him leave the low-security prison he was being held in and travel to the airport, located some 60 miles away.

The mining hardware has not yet been recovered, The Guardian further reported. The owners of the machines have offered $60,000 as a reward for anyone who can help locate the machines.

While a warrant is out for Stefansson's arrest in Sweden, his whereabouts are reportedly unknown at this time.

Prison image via Shutterstock