President Donald Trump lashed out at Sen. Richard Blumenthal Wednesday after the Connecticut Democrat questioned the president on cable news.

Blumenthal went on CNN in the morning criticizing the Republican president and calling for an independent investigation following the abrupt firing of FBI Director James Comey.

"What we have now is really a looming constitutional crisis that is deadly serious," Blumenthal said.

Trump responded on Twitter in a series of three tweets. 

"Watching Senator Richard Blumenthal speak of Comey is a joke," the president wrote. "'Richie' devised one of the greatest military frauds in U.S. history. For years, as a politician in Connecticut, Blumenthal would talk of his great bravery and conquests in Vietnam, except he was never there. When caught, he cried like a baby and begged for forgiveness, and now he is judge and jury. He should be the one who is investigated for his acts."

The Connecticut senator responded to the president's tweetstorm around noon.

"Your bullying won't silence my calls for an independent prosecutor," he wrote.

Later in the day, Blumenthal added, "The people of Connecticut and the country want the truth uncovered."

"The White House is in a bunker right now," said Sen. Chris Murphy, another Connecticut Democrat. "They're coming out swinging against anybody who dares criticize them, as Senator Blumenthal did on the air today."

And experts say the calls for an independent investigation have merit. 

"Perhaps there is something that is being uncovered now about the Russian connection... which perhaps is very troubling and certainly not in the interest of the Trump administration," said Gary Rose, a Sacred Heart University political analyst.

But, he added, "To say it reaches the level of a Watergate-type of conspiracy, I think that's jumping the gun a little bit."