More than one week after the polls closed in Mississippi's hotly contested Republican U.S. Senate primary, the campaign many have called this year's nastiest political fight shows no signs of letting up.

Chris McDaniel, the Tea Party-aligned candidate in Mississippi who refused to concede after losing in last week's GOP primary runoff against incumbent Sen. Thad Cochran, is digging in further. In an email to supporters Wednesday, McDaniel announced he is building an "Election Challenge Fund" to contest what he called a "corrupt" election.

A source on the Cochran campaign fired back in a conversation with Business Insider Wednesday, in which the source dismissed McDaniel as a "clinically diagnosable narcissist" and a scam artist.

"The guy is basically Joel Osteen," the source said of McDaniel in a phone interview Wednesday morning. "He's such a phony, and he's taking advantage of these people to stay in the spotlight. This is such a publicity stunt. He can't stand the fact that he lost."

McDaniel, who is a state senator, surprised many local and national political observers when he refused to concede in a blistering, election night speech last Tuesday. More were surprised McDaniel, who many view as having a bright political future in Mississippi and potentially beyond the state's borders, is mounting this challenge amid the risk of losing support of the national Republican Party.

Official results after last week's election showed McDaniel lost to Cochran by 1.6 percentage points. But McDaniel, who won a plurality of votes in the initial primary on June 3, has contended Cochran ultimately came out ahead after courting Democratic and African-American votes — suggesting everything from illegal vote-buying schemes to illegitimate voter targeting.

Mississippi election law, which mandates runoffs between the top two candidates if no candidate in a primary earns over 50% of the vote, bars people from voting in one party's primary and then crossing over to vote in another party's runoff. Though there are few procedures to enforce this, the law says only people who voted in the Republican primary or didn't vote at all were eligible to vote in the June 24 runoff.

Though he has produced no hard evidence thus far, McDaniel has argued Cochran took advantage of the lax enforcement and encouraged Democrats, whether they voted in their own primary or not, to enter the GOP fray and deliver his slim margin of victory.

The Cochran campaign source attributed these concerns to McDaniel being what they described as "the sorest loser I've ever seen."

"What he's mad about is the fact that he got outsmarted and outworked," the source added. "What happened is, he's been doing a victory lap since June 3, and he thought he was going to be coronated. We went back to work. We kicked his ass, and he's mad about it. He's the sorest loser I've ever seen."

The Cochran campaign may not be taking him seriously, but McDaniel clearly intends to press on with his election challenge. He outlined his plans in a fundraising email to supporters Wednesday.

"We have a long fight ahead of us. I know exactly how long and frustrating court battles can be, but I believe this will be worth it. There is too much at stake to back down from this fight," McDaniel said.

"The problem is that court cases are expensive, and we don’t currently have the resources to mount the legal challenge that this case deserves. Please, take a moment to contribute to the Election Challenge Fund to help me contest this corrupt election."

Thad Cochran. AP McDaniel's campaign has also detailed some specific allegations. Team McDaniel has claimed it has found more than 3,300 voting "irregularities" by examining voter rolls in 38 of Mississippi's 82 counties. Cochran's margin of victory was about 6,700.

"That’s just not true," the source in the Cochran campaign told Business Insider of the supposed number of "irregularities." "Chris McDaniel is a trial lawyer, and he’s acting like one. He’s throwing out false flags and things that just aren’t true, and trying to get them into the news stream."

Indeed, some of McDaniel's claims do appear questionable. For example, at one polling location, the Fondren Presbyterian Church, the McDaniel campaign claimed it found about 200 "irregularities." However, only 37 people voted there in the Democratic primary, meaning the maximum possible number of illegal votes would be 37.

The Cochran campaign has no problem conceding there could be a handful of mistakes and clerical errors on both sides. But the Cochran campaign source said the "idea there is some sort of widespread fraud is just not true."

Still, many Tea Party-aligned groups and conservatives clearly think McDaniel was robbed. Conservative blogger Charles Johnson fueled that impression when he posted an interview Monday night with an African-American man who described himself as pastor in Mississippi. The pastor claimed he bribed black voters to turn out and vote for Cochran. But the interview came with the disclosure that the pastor was paid for his participation, which raised doubts about his claims.

Still, conservative groups latched on to Johnson's interview. FreedomWorks responded to the report by calling on the Justice Department and FBI to investigate the pastor's claims. On Wednesday, the conservative, "anti-voter fraud" group True the Vote filed a lawsuit in federal court against Mississippi's secretary of state and the Mississippi Republican Party.

The Cochran campaign has accused McDaniel of egging on these groups and their supporters. And on Wednesday, the Cochran campaign is holding a press conference in Mississippi to respond to what it called a "meltdown" from McDaniel.

"All this is is a candidate who's a total egomaniac — I really believe he is a clinically diagnosable narcissist," the Cochran campaign source told Business Insider. "This is all about him and his 15 minutes in the spotlight. The second he concedes, the circus moves on."

CORRECTION: An initial version of this story said the McDaniel campaign didn't respond to a request for comment. An email seeking comment bounced back to Business Insider after this story had been published.

