National Republicans invested in a special election for a vacant House seat in Montana were mostly silent Wednesday evening after their candidate, Greg Gianforte, was accused of assaulting a reporter before a campaign event.

BuzzFeed News has reached out to representatives with House Speaker Paul Ryan's political team, with the National Republican Congressional Committee, and with the Ryan-aligned Congressional Leadership Fund.

Each group has a stake in the outcome of Thursday's contest between Gianforte and Democrat Rob Quist. And each group was silent in response.

The Guardian's Ben Jacobs says Gianforte "body slammed" him and broke his glasses after Jacobs tried to ask about Gianforte's opinion on the Republican health care bill. Gianforte's campaign spokesman later released a statement accusing Jacobs of grabbing the candidate's wrist and other "aggressive behavior."

But audio posted by The Guardian is at odds with the campaign's account, and features Gianforte shouting extensively.

Additionally, late Wednesday night, after BuzzFeed News first reached out to the groups, Fox News posted an account from a journalist who was in the room with Jacobs and Gianforte. "Gianforte grabbed Jacobs by the neck with both hands and slammed him into the ground behind him," the Fox News journalist wrote.

Gianforte later was charged with misdemeanor assault.

"Unreal," one GOP source close to a group that has spent money on the race said via text message when prodded about the incident. Asked for an on-record comment, the source replied: "Call the campaign."

It's a sign that Gianforte is on his own in the final hours of the campaign. It's not particularly surprising that the national GOP groups would distance themselves in a potential last-minute crisis. The race between him and Quist already appeared to be closer than most Republicans expected, and party operatives will be eager to blame a loss on a flawed candidate as opposed to a national trend that spells doom in the 2018 midterms.

Doug Stafford, an adviser to Republican Sen. Rand Paul of Kentucky, called the Gianforte campaign's statement "horse shit" on Twitter.