State attorneys should review whether a campaign-spending complaint against the Pacific Resource Partnership Political Action Committee warrants criminal prosecution. There are too many questions swirling about the tactics of the notorious Super PAC to let a small fine and a weak excuse spell the end of it. The state Campaign Spending Commission should refer the case to prosecutors.

That’s not to say that PRP PAC’s flawed bookkeeping definitely rises to the level of a criminal offense. But absent further investigation, the public cannot rest assured.

There’s much more to know about how Super PACs operate in general, and about the inner workings of this one in particular, as these groups spend more and more money trying to elect or defeat candidates in Hawaii.

PRP has been about the highest-profile Super PAC locally since the U.S. Supreme Court’s 2010 Citizens United ruling, which allowed corporations and unions to spend unlimited amounts of money to try to influence the outcomes of elections, as long as the spending is not coordinated with a specific candidate.

The PRP consortium of union carpenters and private contractors, active this election cycle through the group Forward Progress, spent $3.6 million to derail former Gov. Ben Cayetano’s 2012 campaign for Honolulu mayor, opposed to an anti-rail candidate taking the helm of the city and aiming to halt the largest public works project in Oahu’s history.

Cayetano, who lost the race amid the relentless attacks, sued PRP for defamation. The group apologized to Cayetano and donated a total of $125,000 to two of his favorite charities to settle that civil lawsuit.

Still at issue is whether the Super PAC’s failure to report certain political action expenditures in 2012 was a simple oversight, as its lawyer claims, or an intentional omission prosecutable as a Class C felony, as Cayetano asserts; his complaint is pending with the state Campaign Spending Commission.

Commission staff recommended that Cayetano’s complaint be dismissed, because PRP has corrected its campaign finance forms and paid a $1,250 fine. But the commission’s chairman rightly resisted that advice.

The commission must not risk marginalizing this case as if it is merely a bid for revenge by a wronged candidate, in this instance Cayetano. Instead, the commission should recognize the broad public interest in probing these types of complaints to the full extent of the law.

The commission could not muster the three votes necessary to decide last week whether to refer the matter to prosecutors for review, but it will have another chance to do the right thing when it meets Nov. 19.

There seems to be little downside in making the referral. If prosecutors find no grounds to pursue the case based on intent or recklessness, the complaint would return to the commission for disposition. The point is not to rush to close this complaint, but to vet it fully.

Cayetano argues that the PRP PAC schemed to defeat his mayoral candidacy months before it filed formally as a PAC, intentionally failed to state clearly that expenditures were made to oppose his candidacy and intentionally failed to report several hundred thousand dollars of expenditures to hire consultants and public relations people. PRP PAC’s lawyer, by contrast, describes the problem as "a simple reporting issue," essentially a bookkeeping oversight.

When versions of the same events are so starkly different, additional investigation is obviously warranted. As the influence of Super PACs continue to grow in Hawaii, protecting the public interest demands that the Campaign Spending Commission exert its full authority. In this case, that means asking prosecutors to step in and take a look.