Washington (CNN) - Sen. Ted Cruz of Texas is calling for an investigation into the bitter and divisive Mississippi Republican Senate primary contest.
"What happened in Mississippi was appalling," the freshman Republican senator from Texas – a rock star among tea party activists and other grassroots conservatives – said Monday.
"Primaries are always rough and tumble, but the conduct of the Washington, D.C. machine in the Mississippi runoff was incredibly disappointing," added Cruz, who made his comments in an interview on Mark Levin's radio program.
The campaign of state Sen. Chris McDaniel, the tea party-backed challenger who narrowly lost last month's Republican primary runoff in Mississippi to longtime Sen. Thad Cochran said Monday it's building the evidence needed to legally contest those results.
McDaniel narrowly edged Cochran in a June 3 primary, but with neither man cracking the 50% threshold needed to win, the contest moved to a June 24 runoff, which Cochran won by just over 7,600 votes, according to an announcement Monday by the Mississippi secretary of state's office
Cochran's victory was apparently aided by votes from African-American Democrats, who were actively courted during the runoff by Cochran's campaign and allied groups. According to Mississippi law, voters are not required to register with a political party, and anyone who doesn't vote in a primary election can cast a ballot in either party's runoff.
"All of us want to grow the party. But what the DC machine did was not try to grow the party. Instead, the ads they ran were racially charged false attacks and they were explicit promises to continue and expand the welfare state. And nobody has suggested that the Democrats who voted in the primary will actually vote Republican in the general. Instead they were just recruited to decide who the Republican nominee was and that's unprincipled and wrong," Cruz said Monday night.
"These allegations need to be vigorously investigated," Cruz added.
After the runoff, McDaniel's campaign dispatched volunteers across Mississippi to investigate the results in the state's 82 counties. FreedomWorks, one of the anti-establishment groups that's been supporting McDaniel, dispatched activists to assist the campaign. Separately, a conservative outside group filed a lawsuit in federal court asking for full access to the voting records in the primary and runoff elections.
What makes the strong language by Cruz notable is that in title, he is still vice chairman of the National Republican Senatorial Committee, part of the "DC machine" that he railed against. The NRSC is the Senate GOP committee which helps Republican incumbents running for re-election. A Cruz aide says the senator has refrained from raising any money for the NRSC since the committee got involved in contested primaries.
Cruz did not make any endorsement in the Cochran-McDaniel primary battle, but earlier in the election cycle he did support some of the anti-establishment groups that were backing some of the conservatives who launched primary challenges against incumbent GOP senators. For most of this year, with the exceptions of Oklahoma and Nebraska, Cruz has stayed out of Republican Senate primary battles.
CNN Political Editor Paul Steinhauser contributed to this report