The National Republican Senatorial Committee (NRSC) will host a “Thank You Reception” Tuesday for donors who forked over nearly a million dollars to help Sen. Thad Cochran (R-MS) defeat state Senator Chris McDaniel in a June 24 runoff.

The event comes just hours after the NRSC’s Vice Chairman Sen. Ted Cruz (R-TX) called for an investigation into the voter fraud allegations surrounding Cochran’s contentious and controversial win.

“The general election campaign is well underway and contributions are always welcome. However, there is no charge for this event,” the invite reportedly reads. “It is meant as a toast to all those who so generously supported and promoted Senator Cochran’s campaign during the Primary.”

During the runoff election, an NRSC fundraiser reportedly raised “more than $800,000 for Cochran.” Attendees at the event, which Senate Minority Leader Mitch McConnell (R-KY) attended, ran away from Breitbart News reporter Matthew Boyle. The NRSC also reportedly deployed “45 staff members and volunteers” to help the Cochran campaign in the runoff.

Cochran’s campaign actively courted black Democrats and liberal union workers to cross over in the runoff by running incendiary ads linking the Tea Party to the era of Jim Crow and saying the Tea Party would take away food stamps, welfare benefits, and funding for the state’s historically black colleges and universities. The McDaniel campaign alleges that many of those voters had already “voted in the June 3 Democratic primary, then crossed over June 24 and voted in the Republican runoff, which is prohibited by state law.”

After Cochran’s win, emboldened black Democrats at the state and federal levels have demanded that Cochran vote with them on key bills in the next Congress, especially if Cochran becomes the Chairman of the powerful Senate Appropriations Committee if the GOP takes back the Senate.

On Mark Levin’s radio show Monday, Cruz said that the Washington, D.C., machine’s conduct in “Mississippi was appalling” and that the “serious allegations” of voter fraud “need to be vigorously investigated and anyone involved in criminal conduct should be prosecuted.”

“What we know at the outset is that Chris McDaniel won a sizeable majority of the votes from Republicans who voted in the run-off,” Cruz said. “But the DC machine spent hundreds of thousands of dollars urging some 30,000-40,000 partisan Democrats to vote in the run-off which changed the outcome.” Cruz said the D.C. machine did not try to grow the party by courting liberal Democrats and blasted them for ads against McDaniel that “were racially charged false attacks” that made “explicit promises to continue and expand the welfare state.”

Though the election results have been certified, Mitch Tyner, an attorney for McDaniel, told the Clarion-Ledger that “we are surprised by the amount of evidence that continues to come forward that shows us there has indeed been election fraud in this case.”

According to the Clarion-Ledger, “Tyner said he is uncertain the number of ineligible votes the campaign has found. McDaniel’s campaign reported 4,900 late last week, and McDaniel in television interviews said 5,000.”

Acknowledging that Mississippi state law “says a first challenge of election results would be filed with the Mississippi Republican Party executive committee,” Tyner “said that 10 days after a challenge is filed with the party, a lawsuit could be filed in state circuit court to seek a new election.”