He was charged with shooting David Smith, 46, and Mark Anthony Hall Jr., 28, at a mobile home near Hartshorne on December 5, 2010.
Investigators arrested him in October of 2014.
District Attorney Farley Ward told the McAlester News-Capitol two people who had given statements to investigators about Bornheim's alleged involvement recanted.
According to court documents, the Oklahoma State Bureau of Investigation said the killings stemmed from a dispute over a stolen Bobcat skid steer loader.
Court records in Iowa show Bornheim was on probation after a conviction in 2012 for stabbing a man in Iowa Falls when he was arrested for the Oklahoma double shooting.