The fraudulent transactions occurred in Calgary, Toronto, Montreal, Ottawa, Hamilton, Winnipeg and Sherwood Park between September 16th and September 26th, 2018.
Police were notified last October about a number of fraudulent activities that targeted a Canadian bitcoin company and say 112 transactions were made at kiosks in seven cities. The attacks took place in 7 cities across Canada, half of them taking place in Calgary.
The men succeeded in their theft because they exploited the Bitcoin ATMs' zero-confirmation transactions to double-spend Bitcoin in exchange for money.
"All four suspects are described as men and are believed to have in-depth knowledge or interest in cryptocurrency, bitcoin and/or blockchain technology", according to Toronto police.
In the case of this Bitcoin ATM brand, it appears it was crediting unconfirmed transactions to allow money to be withdrawn before it received the suspect's Bitcoin. Though the identities of the perpetrators are not now known, the Calgary police are requesting the public's help in identifying them. While it was not created to facilitate theft, the tool lets "stuck" transactions to become released for the cost of an extra fee.
The second suspect is believed to be responsible for transactions that occurred in Calgary.
Law enforcement teams in Calgary are spearheading a nationwide investigation into a suspected Bitcoin fraud ring that made off with almost $200,000 in a little over a week. That is why services ask for multiple confirmations for every transaction.
The Calgary Police Service is being assisted in its investigation by authorities from Toronto, Hamilton, Winnipeg, and Halton. Further, there is a "double spend" tool that also seems to be at the heart of the transactions.
Individuals with any leads can submit their tips to Crime Stoppers.