About $190m in cryptocurrency has been locked away in a online black hole after the founder of a currency exchange died, apparently taking his encrypted access to their money with him.

Investors in QuadrigaCX, Canada’s largest cryptocurrency exchange, were unable to access their funds after its founder, Gerald Cotten, died last year.

According to a court filing first reported by CoinDesk, a cryptocurrency news and events company, Jennifer Robertson, identified as Cotten’s widow, said the exchange owes its customers roughly C$250m (US$190m) in cash and cryptocurrency held in its “cold storage”.

“Quadriga’s inventory of cryptocurrency has become unavailable and some of it may be lost,” Robertson wrote in the filing.

Cotten, 30, died in India last December from complications from Crohn’s disease, according to the company. He was in India “opening an orphanage to provide a home and safe refuge for children in need”.

The news followed a decision by Canadian Imperial Bank of Commerce (CIBC) to freeze $28m of assets held by Quadriga after saying it was unable to identify the real owners of the funds.

Robertson was not involved in the business. In the filing she noted that there had been a “significant amount of commentary on Reddit and other web based platforms about Quadriga, Gerry’s death (including whether he is really dead) and missing coins”. She said she had also received threats and slanderous comments.

Robertson has access to Cotten’s laptop but writes that she is unable to open it. “The laptop computer from which Gerry carried out the companies’ business is encrypted and I do not know the password or recovery key. Despite repeated and diligent searches, I have not been able to find them written down anywhere.”

Robertson has retained an expert to try to access the funds but he has so far not been able to do so.

The platform continued to accept funds after Cotten’s death but was paused by directors on 26 January.

On 31 January, QuadrigaCX filed an application for creditor protection with the supreme court of Nova Scotia, after months of transaction delays.

At a court hearing on 5 February the company is seeking to appoint Ernst & Young as an independent monitor.