Former U.S. Attorney General Eric Holder sent out a early morning message via Twitter, warning and encouraging “career men and women” at the Department of Justice and the FBI.

“Your actions and integrity will be unfairly questioned. Be prepared, be strong. Duty. Honor. Country,” he said.

To the career men & women at DOJ/FBI: your actions and integrity will be unfairly questioned. Be prepared, be strong. Duty. Honor. Country. — Eric Holder (@EricHolder) June 30, 2017

The tweet comes as the FBI conducts an investigation into whether President Donald Trump’s campaign colluded with Russia to interfere with the 2016 election.