The inquiry, dubbed "Operation Red Sunset," led by the Department of Homeland Security, reportedly examined whether the company's machines could be remotely manipulated for espionage or sabotage of critical US infrastructure. Bitmain denies these capabilities, but investigators have reportedly tested its equipment at ports and dissected chips and code to assess potential threats. The company's hardware has long attracted scrutiny. A 2017 Bitcoin Magazine report suggested Antminer devices contained code allowing remote shutdown, which Bitmain said was a theft-prevention feature later patched.