Police in Calgary, Winnipeg, Toronto, Hamilton, Halton and other Canadian centres after hunting for four men seen above who stole almost $200,000 by employing a trick known as a double spending attack.
The suspects targeted only one Canadian Bitcoin company, police said, stealing $195,000 from the cryptocurrency provider.
The four suspects in the Canadian Bitcoin ATM scam are believed to have figured out of a way to cancel transactions before they were fully processed by the provider of the units.
The pictures were published in CBC, along with a statement from the Calgary police that speculated that the four suspects have "deep knowledge or interest in cryptocurrency, Bitcoin, and/or blockchain technology".
Each of the four suspects are accused of attacks in specific cities. The Calgary Police Service pleads with the public to supply any information relevant to the apprehension of these men. Further, there is a "double spend" tool that also seems to be at the heart of the transactions.
Bitcoin ATMs have been growing in number across the world, with over 4,000 already in operation. The left-most individual in the above image is believed to have focused on Toronto, Montreal, Ottawa, and Hamilton. While not designed for criminal applications, the tool is described by Todd as a means of creating successive transactions to smooth "stuck" transactions.
The second suspect is believed to be responsible for transactions that occurred in Calgary. In addition, you can optionally specify that the first transaction additional OP-RETURN, multisig, and "blacklisted" address outputs.
None of these companies confirmed if they allow for 0-confirmation transactions or not.
The Calgary Police Service's cybercrime team has been leading a national investigation into the fraudsters since October with assistance from agencies across the country, including the Toronto Police Service, Hamilton Police Service, Winnipeg Police Service and Halton Regional Police Service. All pertinent information regarding the suspects can be anonymously submitted to the police.