Twice in six years, state Rep. Romy Cachola has been accused of effectively stealing elections by intimidating elderly immigrants in his Kalihi district to vote for him via mail-in ballots.

The charges are concerning enough to warrant investigation by the state attorney general, the U.S. attorney and the House itself to insure the integrity of our elections.

After the Aug. 11 Democratic primary, 47 unidentified voters filed suit asking the state Supreme Court to overturn Cachola’s 51-vote victory over Sonny Ganaden, alleging election fraud and vote tampering by Cachola.

The plaintiffs claimed Cachola’s slim victory margin came from “a suspicious and irregular submission of last-minute ‘mail in drop off’ ballots which were counted after 3 a.m. the morning after the election.”

They charged that Cachola runs his campaign out of his wife’s medical clinic and coerces elderly patients to cast absentee ballots for him under “the implicit threat of diminished health care.”

The Supreme Court dismissed the suit, saying it has limited powers to overturn election results and isn’t the right venue to adjudicate the alleged criminal activities.

But justices made clear that “these allegations are serious and may warrant further investigation” by appropriate state and federal authorities.

In 2012 Cachola beat Nicole Velasco by 120 votes, also with an unusually high advantage in mail-in votes and allegations of intimidating elderly voters and helping with their ballots.

The next year, the Legislature passed a measure dubbed “The Romy Cachola Bill” prohibiting candidates, unions or employers from assisting voters with completing absentee ballots.

Last month Honolulu Civil Beat reported that Cachola acknowledged handing out absentee ballot application forms to prospective voters and helping mail in completed forms.

“Sometimes if they are more or less disabled, cannot walk, (and they ask), can you just submit it or mail it, I’ll mail it,” he was quoted as saying. “But you know what, it’s allowed.”

The plaintiffs who sued Cachola, who next faces Republican Mar Velasco, claim firsthand knowledge of substantial violations of state and federal election and health care laws. They deserve a fair hearing by the attorney general and U.S. attorney, with charges pursued if warranted.

And as the Supreme Court noted, the Legislature has constitutional power to “be the judge of the elections, returns and qualifications of its own members,” and punish violations with censure or expulsion.

A House committee should hear the complainants, examine evidence — by subpoena if necessary — and once and for all get to the bottom of recurring allegations that one of its members is corrupting elections.

The majority in Hawaii already votes by mail, and the Legislature is considering making all elections that way. We need to secure the integrity of mail-in voting by making examples of those who abuse the process and closing loopholes that enable them.

Reach David Shapiro at volcanicash@gmail.com.