Mueller is trying to determine if Trump’s campaign advisers colluded with the Russian government to influence the election. The investigation also reportedly involves a probe into whether the President obstructed justice when he allegedly asked ex-FBI director James Comey to drop an inquiry into former National Security Adviser Michael Flynn. 

Flynn pleaded guilty in December to lying to the FBI about his conversations with the Russian ambassador, becoming the first senior White House official to cut a cooperation deal in Mueller’s inquiry. 

Now Trump’s legal team is pushing for a written question and answer, multiple media reports said. The White House and Trump has been saying that he is ready to cooperate as he has nothing to hide.