According to a Democratic source who just called me, King 5 news is planning to report this evening that a new SurveyUSA poll finds Republican Dino Rossi beating Washington's senior Democratic senator, Patty Murray, by a large margin: 52-42.

The source, who claimed to have received a courtesy call from King 5 this afternoon in which the results were shared, said the poll is unusual in that it was conducted all in one night. It also used a relatively small sample: only 517 people. This source, clearly ready to go to war with SurveyUSA over a poll that will be dangerous for Murray if taken seriously, also shared a raft of oppo research on the polling organization, including that a 12-year-old boy could convince its computerized phone calls that he's a 37-year-old woman and that respected news organizations won't use its results. "KING 5’s own national news division—NBC News—won't air results from SurveyUSA," the source added. "Neither will CBS or ABC."

Asked about the alleged poll results, Alex Glass, spokesperson for Patty Murray, said: “This poll is a complete outlier. It matches up with nothing that we’ve seen either internally or publicly. I think the poll is not accurate.”

It definitely doesn't match up with the latest from Rasmussen, which found Murray leading Rossi 48-46.

A big caveat, obviously: We won't know for sure what this alleged SurveyUSA poll says, or how it was conducted, until it's published.