Aubrey McClendon, former chief executive officer of Chesapeake Energy Corp and a legend in the U.S. energy industry, was charged on Tuesday with conspiring to rig bids to buy oil and natural gas leases in Oklahoma, the Justice Department said. The indictment follows a nearly four-year federal antitrust probe that began after a 2012 Reuters investigation found that Chesapeake had discussed with a rival how to suppress land lease prices in Michigan during a shale-drilling boom.