In June, Big Island residents posted video online showing a tour boat owner using a backhoe on the century-old Punaluu Wharf.
Resident say he told them he was widening the boat ramp to accommodate a lava tour. The postings ignited a public outcry and a multi-agency investigation.
Now, Hawaii County's Planning Department has issued $15,000 in fines in a violation notice to the landowner, SM Investment Partners, which is a sister company to Roberts Hawaii.
The document said the boat owner had "demolished two historic concrete structures."
"They did notice deposited material like remnants of concrete structure that was destroyed as well as a toppled stack rock wall," said Daryn Arai, deputy director at County of Hawaii Planning Department.
Ka'u resident Demetrius Oliveira said the fine is a "step in the right direction."
"What happened with this case would set a precedent and a deterrent for any and all companies that become a party to the desecration of the aina."
But SM Investments lawyers blamed the tour boat owner, Simon Valej, and said the landowners didn't give him permission to excavate.
They're now threatening to sue the county if they don't withdraw the fines. A letter to the planning department said the "county issued fines against SM Investments knowing another party was responsible."
Arai disputes SM Investments' claims.
"The landowner in our eyes is ultimately responsible for compliance with our land use laws," said Arai.
Councilwoman Maile David agrees and believes the Ka'u community should be commended.
"I think the community in this day and age have become the eyes and ears of government and I really applaud that," she said.
Meanwhile, the state Land Department and U.S. Army Corp of Engineers are also investigating.
Valej has previously told Hawaii News Now he was only cleaning the area. He did not respond to a request for comment.