U.S. Attorney General Jeff Sessions was questioned last week by the special counsel’s office investigating potential collusion between Russia and President Donald Trump’s 2016 presidential campaign, the U.S. Justice Department said on Tuesday.The interview marked the first time that Special Counsel Robert Mueller’s office is known to have interviewed a member of Trump’s Cabinet, and is another milestone in an investigation that has hung over Trump’s year-old presidency.Mueller’s office also interviewed former Federal Bureau of Investigation Director James Comey shortly after Trump fired Comey in May 2017, a person familiar with the matter said.