The Democratic Congressional Campaign Committee is calling for an “uprising” by voters to protect special counsel Robert Mueller’s investigation in light of the latest developments.

In an email sent to supporters on Saturday, the DCCC warned of the fate of Mueller’s probe into alleged Russian collusion in the 2016 election and President Donald Trump’s campaign, calling for immediate action to protect the special counsel after the arrest of Roger Stone.

Noting that the Trump ally’s arrest last week could spell trouble for the investigation, the DCCC expressed “serious concern” to email recipients, according to the Washington Free Beacon.

“There is now serious concern that Trump or his allies could retaliate against Robert Mueller,” read the message from the official campaign arm of the Democrats in the House of Representatives.

DCCC calls for “MASSIVE uprising” following developments in Mueller probe: pic.twitter.com/jvlVDjBRB2 — Mikhael Smits (@mikhaelsmits) January 27, 2019

The email urged “a MASSIVE uprising,” calling on supporters to sign their names “immediately” in an effort to reach “2 MILLION signatures before midnight” to protect Mueller’s investigation. There was no further explanation of what the signatures would accomplish but there were purportedly 1.56 million out of the target 2 million reached as of Monday according to the website.

Stone, a former political adviser to Trump was arrested Friday after being indicted by a federal grand jury on seven counts including obstruction, making false statements and witness tampering in the ongoing Russia investigation. Missing in the list of charges, however, were any indicating collusion.

‘Pretty obvious’: Bongino talks Roger Stone arrest, says there’s one thing that ‘leaps out’ to him over raid https://t.co/ZNDyDyvOFs pic.twitter.com/dPLm8tDh1f — Conservative News (@BIZPACReview) January 25, 2019

Democrats introduced the Special Counsel Independence and Integrity Act earlier this month in order to protect Mueller from being fired by Trump, a move Senate Majority Leader Mitch McConnell thinks is highly unlikely, according to The Hill. The Senate has repeatedly blocked similar legislation.