Cyber security firm Kaspersky Lab on Monday said it had obtained digital evidence that bolsters suspicions by some researchers that North Korea was involved in last year’s $81 million cyber heist of the Bangladesh central bank’s account at the Federal Reserve Bank of New York.

Russian-based Kaspersky released a 58-page report on Lazarus, a group linked to the heist in Bangladesh and the 2014 attack on Sony’s Hollywood studio, which the U.S. government blamed on North Korea.

Among its findings, the report said Lazarus hackers made a direct connection from an IP address in North Korea to a server in Europe that was used to control systems infected by the group.

Kaspersky researcher Vitaly Kamluk told Reuters by telephone that the finding marked “the first time we have seen a direct connection” between North Korea and Lazarus, a hacking group whose activities dating back to 2009 have been documented by the world’s biggest cyber security firms.