(CNN) - When the heavy rainstorms hit the Hawaiian island of Kauai, teams of volunteers climbed into their boats and got to work, rescuing those who found themselves trapped.
But some of those rescued said they were the victims of a scam when they were told to either pay or be left stranded.
Kauai Police said Friday those complaints led them to arrest boat operator Stephen Koehne, 33, on suspicion of extortion, robbery and terroristic threatening. He has not been formally charged.
Koehne's passengers were under the impression that he was ferrying them to a safer place, officials said. But when he made it approximately 200 yards offshore, he allegedly would demand money.
"Two hundred bucks a head, cash or credit, or we're going to leave you here," Kauai County Prosecuting Attorney Justin Kollar said Koehne told the passengers.
The Kilauea man has been released but his boat, the 25-foot Riddle, is being held as evidence.
Koehne's brother, Joey, said he strongly denies the charges, characterizing it as a misunderstanding.
"He was out in his boat helping people," Koehne's brother said. "He's a good person. It's not true, and it's not fair."
Multiple extortion complaints first started in Haena, a part of Kauai where the main access road was washed away over the weekend, Kollar said. Police became aware of the alleged scheme after residents and tourists began sharing social media posts on Sunday. The investigation is ongoing.
"Those conducting illegal activities will be held accountable for their actions," Kauai Deputy Chief Michael Contrades said in a statement.
Hundreds of people have been evacuated from flood-stricken areas of the island after severe rain struck last week.
Kollar said it's disheartening that someone from their community would do this, especially while the area works to rebound from this crisis.
"One of the best things about our community is how we come together in times like this," he said. "This kind of conduct, especially from somebody who is from this area, is completely unacceptable."
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