Evidence is mounting that Donald Trump attempted to obstruct justice with his actions involving the recently fired FBI Director James Comey. A growing number of Members of Congress and legal experts are speaking out.

Donald Trump stepped in political quicksand when he fired FBI Director James Comey, the man in charge of investigating possible Trump campaign coordination with Russia. But his efforts to extricate himself may have landed him in a deeper pit of legal jeopardy.

The firing itself could be evidence of obstruction if Trump removed Comey in order to derail Comey’s investigation of Trump, as many have suggested.

The reason for the firing was initially cloaked in the thin veil of an absurd rationale. However, Trump’s team, and indeed, the president himself, have completely destroyed that first excuse already.

After Trump and his administration spent several days lying about the reason Comey was fired, Trump openly admitted the Russia investigation was part of his consideration during an interview with NBC News’ Lester Holt.

Trump also described the occasions when Comey allegedly offered assurances that Trump was not under investigation, including a dinner at which Comey’s continued employment was being assessed.

Deepening the obstruction quagmire for Trump is a New York Times report about the dinner Trump referenced. During that dinner, Trump repeatedly asked Comey for a pledge of “loyalty,” which Comey refused to give. The Times also says it was Trump, not Comey, who requested the dinner, and makes no mention of any assurances from Comey beyond “honesty.”

Now, Trump is attempting to silence Comey with threats to release “tapes” of the dinner, sending clear messages to the FBI — and Comey’s eventual successor — that he wants this investigation to end.

A source has since told CNN that Comey is “not worried about any tapes.”

The Comey firing and subsequent fallout has a number of congressional Democrats and others speaking out about the possibility that Trump obstructed justice, one of the charges that brought down former President Richard Nixon.

Rep. Maxine Waters (D-CA), constitutional law expert Laurence Tribe, Rep. Eric Swalwell (D-CA), Sen. Richard Blumenthal (D-CT), and Sen. Ron Wyden (D-OR) are just some of the prominent voices raising this concern:

WATERS: Absolutely, I think he can be looked at, and perhaps even charged with, obstruction of justice.

TRIBE: That is clearly, on its face, obstruction of justice.

SWALWELL: This is a pattern of obstruction we’ve seen from the president.

BLUMENTHAL: Impeding the investigation, obstruction, cover-up, call it what you will.

WYDEN: There are questions with respect to the technical definitions of obstruction of justice, but it sure looked like this firing was to make this entire investigation just go away.

Meanwhile, the watchdog group Citizens for Responsibility and Ethics in Washington (CREW) is calling for an obstruction of justice investigation into Trump. In a letter to Deputy Attorney General Rod Rosenstein, they urge the appointment of a special counsel, stating that “given the emerging and troubling evidence of potential obstruction, we believe that there is no acceptable alternative to an immediate and credible investigation to resolve these questions.”

The letter declares that such an investigation is necessary for the country “to have confidence in its leadership and its institutions.”

Republicans have been very slow to come around on the idea of a special prosecutor, but Trump’s actions this week have given that issue a new sense of urgency, as well as a new impetus for Democrats to push for Trump’s impeachment:

The time has come for Republicans to put country ahead of party and support the kind of independent investigation that could result in Trump’s impeachment.