Following the recent sudden disappearance of Poland’s one of the oldest and largest bitcoin exchange Bitcurex, prosecutors have launched an investigation.

Bitcurex went offline earlier this year, with its users losing access to their 2,300 bitcoins reportedly. Local news source Gazeta reported that the circumstances of the disappearance of the exchange are “mysterious”. Problems first started appearing in October 2016, when users had problems to log in to their accounts. Bitcurex said at the time that its third party systems service was damaged by “external interference in automated data collection and processing of information”, resulting in the loss of part of the assets managed by it. It promised to return customer funds within 7 days, which never happened.

In a statement, prosecutors in Łódź, Poland, said that it is investigating the case on suspicion of crimes against the property of third persons, CoinDesk reported.

"Victims who have not submitted previously reporting a crime may direct such notice directly to the District Prosecutor's Office in Lodz - by mail," the statement said (loosely translated). "For written notices should be if possible, attach copies of the documentation or printouts confirming the amount of damage suffered (BTC balance, confirmations transfers PLN or other currencies)."

Established in 2012, Bitcurex was operated by a Łódź-based company called Digital Future. The exchange had been under hacking attacks a number of times over the past few years, forcing it to suspend services temporarily.