The National Police of Ukraine has disclosed an international cybercrime operation tied to the theft of nearly 30,000 customer accounts belonging to a California-based online retailer, authorities said this week. According to Ukraine’s Cyber Police Department, investigators identified an 18-year-old resident of Odessa who allegedly played a key role in a large-scale account theft scheme involving stolen session data, malicious software, and unauthorized online purchases that caused millions of hryvnias in losses.

The investigation was conducted by cyber police officers in the Odessa region and the Main Investigation Department of the National Police under the procedural guidance of the Pr...