Donald Trump Jr.Donald (Don) John TrumpNadler: I don't understand why Mueller didn't charge Donald Trump Jr., others in Trump Tower meeting Impeachment? Not so fast without missing element of criminal intent House Dem calls on lawmakers to 'insulate' election process following Mueller report MORE took to Twitter on Sunday to troll House Intelligence Committee Chairman Adam SchiffAdam Bennett SchiffSchiff rips Conway's 'display of alternative facts' on Russian election interference Schiff: Mueller report 'far worse' than Watergate Schiff: Democrats 'may' take up impeachment proceedings MORE (D-Calif.) hours after Attorney General William Barr delivered a summary of special counsel Robert MuellerRobert Swan MuellerSasse: US should applaud choice of Mueller to lead Russia probe MORE’s investigation to Congress.

As lawmakers from both sides of the aisle reacted following Barr’s summary of Mueller’s lengthy investigation into collusion between the Trump campaign and Russia to interfere in the 2016 election, Trump Jr. knocked Schiff for remaining quiet.

“Has anyone heard from slimy Adam #fullofschiff Schiff today?” Trump Jr. wrote in a post on Twitter Sunday evening. “I mean it must be embarrassing to have have spent the last 2 years as the leader of the tinfoil hat brigade and have it all come crashing down so quick.”

Trump Jr. borrowed the “full of Schiff” reference from his father. President TrumpDonald John TrumpThorny part of obstruction of justice is proving intent, that's a job for Congress Obama condemns attacks in Sri Lanka as 'an attack on humanity' Schiff rips Conway's 'display of alternative facts' on Russian election interference MORE has consistently ripped the California lawmaker, who is leading a congressional investigation into Trump.

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Trump’s son added that he is “legitimately concerned for his mental state,” referring to Schiff.

On Sunday morning, before Barr delivered his letter to Congress, Schiff said Congress would have to consider impeaching Trump if Mueller’s report found “overwhelming evidence of criminality” on Trump's part.

According to Barr’s letter, which summarized the conclusions from Mueller’s investigation, there was no evidence of collusion between the Trump campaign and Russia to interfere in the 2016 election.

The letter says that Mueller did not make a conclusion as to whether Trump obstructed justice in the investigation of Russia's election interference, though Barr and Deputy Attorney General Rod RosensteinRod Jay RosensteinKellyanne Conway: Mueller didn't need to use the word 'exoneration' in report Impeachment? Not so fast without missing element of criminal intent Collins: Mueller report includes 'an unflattering portrayal' of Trump MORE decided they would not pursue an obstruction of justice charge against Trump.