Comey later testified that he'd authorized a friend to disclose to the media his notes on conversations with Trump about the investigation, in hopes that it would lead the Justice Department to name a special counsel.
Sanders, for example, was asked if Trump still felt "vindicated" by the extraordinary congressional testimony last week by James Comey, the Federal Bureau of Investigation director whose firing by Trump has contributed to questions about whether the president obstructed justice.
"Mr. Trump's apparent reference to Mr. Rosenstein, who oversees the Russian Federation investigation because Attorney General Jeff Sessions recused himself from it, came just hours after an oddly worded statement from Mr. Rosenstein complaining about leaks in the case".
"He's driving this", the White House official said, speaking on condition of anonymity to discuss West Wing internal deliberations.More news: Donald Trump Jr. appears to contradict father's account of private Comey meeting
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More news: Pres. Trump acknowledges he's being investigated
Now as the president returns to the White House in this hour, one question above all that he's facing is what is his relationship with the Deputy Attorney General Rod Rosenstein? Witch hunt. Now, some news outlets have taken that last tweet as confirmation from the president himself that, in fact, he is under investigation. Pence headed the Trump transition until Inauguration Day.
But the probe won't be exclusively focused on Trump-land.
Trump also reportedly asked Director of National Intelligence Dan Coats and CIA Director Mike Pompeo to intercede with Comey on the Flynn case, then later asked Coats and National Security Agency chief Mike Rogers to state publicly that Trump was not personally under investigation. That is why investigators want to know more about a meeting between Trump's son-in-law Jared Kushner and executives of Vnesheconombank, a Russian state-owned development bank now under US sanctions.
It was not clear whether the president was basing his tweet on direct knowledge, or on reports this week that special counsel Robert Mueller is examining whether he obstructed justice by firing Mr Comey last month amid the Russian Federation investigation.
Rosenstein came to be the top law enforcement official with regard to the investigation into Russian interference in the 2016 elections after he was sworn in in April. He says, the fake news hates it when I use social media, but it's turned out to be very powerful.
He has decided - after consulting with a small circle of advisers in multiple meetings over the last few days - that "this is a political fight and he's going to fight it", the official said. He also has millions of followers on his official Facebook pages.
Trump has called The Washington Post report a "phony story" and a "WITCH HUNT". Grassley also wants the investigation to look at Obama attorney general Loretta Lynch and whether she influenced the Clinton email scandal investigation.