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The Justice Department (DOJ) has launched an investigation into longtime Trump advisor Corey Lewandowski , a source familiar with the matter told Fox News.

The probe stems from a criminal referral sent to the Justice Department by the Department of Homeland Security’s inspector general, marking a legal escalation for the high-profile political figure.

Asked about the inquiry by reporters outside the White House, President Donald Trump said he wants his staff held accountable and that he had "heard something about it."

"All I know is I want my people to be honest," Trump said.

TRUMP'S NEW PRESS SECRETARY OUT OF A JOB JUST DAYS AFTER ROCKY DEBUT

The Justice Department has launched an investigation into Corey Lewandowski, a longtime advisor to Donald Trump, a source told Fox News.…