The U.S. Department of Justice has arrested the CEO and the chief financial officer of a Malden medical device company on charges of conspiracy and violation of an anti-kickback law. SpineFrontier Inc. CEO Kingsley Chin, 57, of Fort Lauderdale, Florida, and CFO Aditya Humad, 36, of Cambridge, were arrested Tuesday, following an Aug. 30 indictment. They were charged with one count of conspiracy to violate the anti-kickback law, six counts of anti-kickback violations and one count of conspiracy to...