"What I can tell you is that the [Department of Defense] Office of Inspector General has initiated an investigation into allegations related to Rear Admiral (Lower Half) Ronny L. Jackson," Allen said as quoted by The Hill.
Jackson, who was US President Donald Trump’s pick to lead the Department of Veterans Affairs, withdrew his nomination amid allegations of drinking on the job and overprescribing medications.
The former White House doctor called the allegations "completely false and fabricated," adding that if the allegations against him were true, he would not have served as a physician for three presidents.
Trump said in an April interview that all of the allegations of professional misconduct against his former nominee for Veterans' Affairs Secretary were false.