A new, mysterious “dark money” group is running television ads attacking Democratic gubernatorial candidate Chris Giunchigliani just days ahead of the start of early voting — but hasn’t registered with either state or federal election officials.

The ads, which are paid for by a group called “United for a Better Tomorrow,” began running on Tuesday, and largely echo previous attack ads against Giunchigliani, accusing her of being a “career politician” who voted four times to raise her own pay.

The ad states that she’s up for another pay raise on July 1 and ends by asking voters to call her commission office and tell her to stop “taking pay raises and perks.” Under a law passed by the 2015 Nevada Legislature, the salaries of elected county officials — including county commissioners — are set to be automatically raised by about 3 percent every fiscal year, meaning her hourly salary will go from $42.03 an hour to $43.29.

Although the ad doesn’t directly tell voters to support or oppose Giunchigliani, it’s timing is clear — early voting for the primary election begins on Saturday.

United for a Better Tomorrow doesn’t appear on the Nevada secretary of state’s database of registered PACs. It also doesn’t turn up in the Federal Election Commission’s registry of PACs, nor through a search of the Internal Revenue Service’s database of registered charities.

It also has no obvious online or social media presence — a veritable ghost of an organization, outside a handful of details listed in filings with the Federal Communications Commission.

The group lists a Tennessee address shared by Blue Wave Political Partners, a fundraising and financial compliance firm for high-profile Democratic candidates, including Vermont Sen. Bernie Sanders. Lora Haggard, a partner at the firm and the person listed as the group’s treasurer, declined to answer questions when reached by a Nevada Independent reporter.

It’s not unusual for dark money groups to dump significant sums into races at the last moment. Ending Spending, a political nonprofit founded by TD Ameritrade founder Joe Ricketts and Las Vegas Sands CEO Sheldon Adelson, spent more than $1.5 million on TV ads in the final weeks of the 2016 primary election in an ultimately unsuccessful effort to boost Republican state Sen. Michael Roberson past the eventual winner, Danny Tarkanian.

A similar dark money group called Alliance for America’s Future ran $200,000 worth of television ads promoting gubernatorial candidate Brian Sandoval in 2010, but was forced to reveal its donors and pay a $40,000 fine in 2014 after former Secretary of State Ross Miller challenged the group’s status and said it should have to register as a PAC.

In an email, UNLV political science professor David Damore cited the 2010 ads supporting Sandoval and the long amount of time it took to resolve that situation, and said a similar situation may be brewing during this election cycle.

“My guess is we are going to see lots and lots of this type of stuff this cycle as groups keep pushing the disclosure boundaries, knowing that even if action is taken, the punishments are likely to be minimal at best,” he wrote.

Wayne Thorley, the Deputy Secretary of State for Elections, said his office would likely consider the ad and its content to fit under the state’s description for a political action committee, and that state law required PACs to register with the office within seven days of either raising or spending $1,500.