A senior Republican on the Senate Judiciary committee is demanding that U.S. Drug Enforcement Administration chief Anne Milgram address allegations of improper hiring and contracting of her past associates. The request Thursday by Sen. Chuck Grassley of Iowa follows an Associated Press investigation finding that a federal watchdog is investigating whether strict federal rules on no-bid contracting and hiring may have been violated to channel DEA work to Milgram’s associates. “These are serious allegations, and DEA must respond to them and clear the air,” Grassley wrote in a letter sent to Milgram’s office, a copy of which was obtained by...