The resignation of a KiOR board director has exposed allegations that the advanced biofuels firm knew in the spring of 2012 that its facility in Columbus, Miss., would not reach production targets but didn’t tell investors. The former director, Paul O’Connor, was one of the inventors of the technology that KiOR purchased for the plant. He was employed by the firm and served on its board off and on from 2008 to 2014. O’Connor’s claim appears in a resignation letter, part of a heavily redacted filing by KiOR with the Securities & Exchange Commission. In the filing, KiOR claims it forced O’Connor to resign because he withheld a third-party technology report from the firm and failed to comply with its insider trading policy. SEC issued two subpoenas to KiOR this year as part of a formal investigation. Separately, a group of investors who bought stock in KiOR between August 2012 and August 2013 is suing the company for allegedly misleading them about the timing of production projections. During the period, KiOR’s stock price sank to $4.76 from $6.86. It is now trading at 11 cents.