 Henry Rogers died suddenly in 1909 of a stroke, but William Rockefeller brought in his son Percy Rockefeller to help with leadership.In 1912 and 13, the Pujo Committee investigated William Rockefeller and others for allegedly earning $30 million in profit through cornering of the copper market and "synchronizing with artificially enforced activity" in Amalgamated Copper stock in the New York Stock Exchange.During the 1920s, metal prices went up and mining activity increased.