One would think that a super PAC that has emerged as third biggest outside spender in Hawaii’s U.S. Senate race would be anything but anonymous.

Working Families for Hawaii has spent more than $70,000 supporting Democratic candidate Mazie Hirono, including nearly $34,000 on radio spots bashing former Democratic primary candidate Ed Case.

The other outside spenders in this race are household names: the University of Hawaii Professional Assembly, the U.S. Chamber of Commerce and the Sierra Club.

But this one? Its name isn’t so familiar. In fact, it’s virtually nonexistent on the Internet, save for a handful of websites that reproduce campaign finance data extracted from the Federal Election Commission (FEC) database.

The political action committee has clear ties to at least two major Hawaii labor unions — the International Longshore & Warehouse Union and the Hawaii Government Employees Association. But strangely, neither was willing to take credit for their involvement with the group.

Jodi Endo Chai, a spokesperson for HGEA, said she hadn’t even heard of it.

“I don’t have any knowledge of the PAC you mentioned,” she wrote in an email. “I would suggest that you check the filing for the committee’s contact information.”

Working Families’ “Statement of Organization,” available on the FEC website, provides a few clues.

The form lists no phone number, but does provide an email address: workingfamiliesforhawaii@gmail.com. We sent an email to that address Aug. 3. We’re still waiting to hear back.

The form lists the HGEA as a “connected” organization. And subsequent FEC filings show that HGEA in June and July gave the super PAC $721. The contributions were itemized as “Administrative/Salary Costs.”

Working Families’ organizational report states that a woman named Maureen Wakuzawa is the super PAC’s custodian of records. As it turns out, Wakuzawa is the financial services controller at HGEA.

But she didn’t return numerous calls for comment.

The form does name Guy Fujimura as the group’s treasurer. Fujimura is the secretary and treasurer of Hawaii’s ILWU.

He didn’t return our calls, either.

We also reached out to Hirono’s campaign.

“We have no information on them,” wrote Carolyn Tanaka, Hirono’s former deputy campaign manager, in an email.

Go figure — super PACs are independent expenditure-only committees, meaning they don’t work in coordination with any candidate or candidate’s committee.

Low profile or not, Working Families has been an active player in this election, filing required financial disclosures — even 24- and 48-hour notices in accordance with FEC regulations.

The super PAC in 2010 also spent $241,000 supporting Colleen Hanabusa‘s congressional campaign.

Other than radio spots — both in support of Hirono and in opposition to Case — Working Families this year has spent about $2,700 on yard signs.

An advertising firm called Hendrix Miyasaki Shin Advertising donated about $2,300 to the super PAC back in February. The group’s biggest donor is the American Federation of State, County and Municipal Employees, a national Washington, D.C.-based public services employees union affiliated with HGEA. The union in June gave the group $200,000.

Neither of those donors returned our calls for comment.

We’ll wager that this won’t be the last we see of the super PAC. As of late July, Working Families of Hawaii had about $137,000 cash on hand.

Alia Wong previously covered education news for Civil Beat. A Honolulu native, Alia returned to the islands in May 2012 after graduating from Boston University with degrees in journalism and Latin American studies. Alia was a longtime intern at Civil Beat before landing her position as a reporter-host....