The Washington State Patrol is investigating whether Snohomish County Executive Aaron Reardon misused public funds for travel, throwing another accusation into an already nasty election fight less than a week before ballots are due.

Snohomish County Prosecutor Mark Roe said Thursday the accusations are unproved. He said he asked the state to investigate after learning of "evidence" from someone who allegedly had firsthand knowledge.

Reardon, a Democrat seeking his third term, said he has done nothing wrong and blamed the allegations on his opponent, state Rep. Mike Hope, R-Lake Stevens.

"I'm furious that we have someone who's decided to file an allegation four days before an election," Reardon said. "I do not know who filed it, but the timing is very curious. The fact that the State Patrol won't have time to conclude their investigation before the election is outrageous."

He added: "I don't have any doubt that my opponent's campaign is behind this."

Hope said he had nothing to do with it.

His campaign learned about the investigation from someone who had been interviewed by State Patrol investigators, said Hope's campaign manager, Jason Chambers.

Hope, a Seattle police officer, has raised questions for months about Reardon's travel, accusing him in ads and campaign fliers of "corruption."

The State Patrol investigation was prompted by someone from Reardon's own political party: Dave Somers, the Democratic chairman of the Snohomish County Council, who said he received "credible information" two or three weeks ago from someone he hadn't met previously.

Somers said he had no indication the person is tied to Hope's campaign or politically motivated.

He passed the information on to Roe, who said he discussed the situation with a State Patrol detective and captain he had known for some time. In an Oct. 26 letter to State Patrol Chief John Batiste, Roe wrote that the two officers asked him to make a formal request for help.

Somers acknowledged the timing was "terrible."

He wouldn't give details about the allegations because, he said, it could interfere with the investigation.

The allegations are generally about travel, Somers said, but are different from Hope's claims that Reardon overspent county money on a 2005 trip to Paris.

Asked whether the allegations were related to Reardon's international travel for trade missions, Somers said, "that might play into it, but that's not the main thing."

Although Somers and Roe are in the same political party as Reardon, they have not always been his allies.

Roe said Reardon supported his election opponent last year. Somers and the rest of the County Council have clashed with Reardon on the budget and other issues.

Hope ran a television ad this fall accusing Reardon of spending $14,000 on a Paris trip.

Records released by the executive's office showed that while Reardon has taken two taxpayer-funded trips to Paris, neither cost anywhere close to $14,000.

Last summer, the state Public Disclosure Commission fined Reardon for failing to disclose a trip to the United Arab Emirates.

Roe said he was sensitive to the fact the election is Tuesday when he asked for an investigation, but said he doesn't make decisions for political reasons.

"Did it cross my mind that this is more high jinks and shenanigans in a campaign that's already had plenty of them? Absolutely," Roe said.

But he said he had a responsibility to pass on the information.

In his letter to the State Patrol requesting an investigation, Roe wrote that the situation was "highly sensitive."

"Even the existence of an investigation could have significant impacts on the individuals involved, and even on county government as a whole," he wrote.

State Patrol spokesman Bob Calkins said the investigation likely will not be completed by Tuesday. "It's more important that we do this right than that we do this fast," he said.

Emily Heffter: 206-464-8246 or eheffter@seattletimes.com