Rogue employees of a Chicago company that specializes in negotiating ransoms to mitigate cyber attacks were carrying out their own piracy in a plot to extort millions of dollars from a series of companies, prosecutors say. Kevin Tyler Martin, a ransomware threat negotiator for River North-based DigitalMint at the time of the alleged conspiracy, was among two men indicted in the scheme. A suspected accomplice who wasn’t indicted was also employed at DigitalMint, court records show.