Kroger board member Ron Sargent is taking the helm at the nation’s largest supermarket chain as questions about the former Kroger CEO continue.

Kroger CEO Rodney McMullen is resigning following a probe into his personal conduct, the grocery chain said Monday. McMullen, who was both the chairman and CEO, is out after a company board investigation found that his personal conduct,

Lead director Ron Sargent, 69, was named chairman and interim CEO effective immediately. The company has also initiated a search for a permanent replacement, it said in a statement. Sargent has been a director since 2006 and formerly served as CEO of Staples Inc.