Attorney General William Barr has appointed a U.S. attorney to examine the origins of the Russia investigation and determine if intelligence collection involving the Trump campaign was “lawful and appropriate,” a person familiar with the matter told The Associated Press on Monday.

In the letter, Mueller expressed frustration to Barr about how the attorney general was portraying the investigation's findings:

Barr defended his decision to step in and clear the president of obstruction of justice after Mueller's report presented evidence on both sides — but didn't reach a conclusion.