Behind Lake Point was George Lindemann Jr., a billionaire real estate investor and heir to a cellphone and cable TV fortune. He served prison time after being convicted in 1995 of paying a man $25,000 to electrocute his horse so Mr. Lindemann could collect a $250,000 insurance payout.

Mr. Lindemann’s consortium wanted to mine for limestone and use the leftover pits to store lake water and clean its pollution, which would otherwise be flushed down the fragile St. Lucie Estuary, contributing to toxic algae blooms. The South Florida Water Management District and Martin County signed off on the project.

But a few years later, Lake Point partnered with another company to try to sell the water to the city of West Palm Beach, troubling Ms. Hurchalla and Martin County officials, who questioned whether the revised plan would really result in environmental benefits. (West Palm Beach ultimately did not buy Lake Point’s water.)

Ms. Hurchalla fired off emails to county commissioners encouraging them to get out of the agreement with Lake Point, arguing that it would destroy wetlands and noting that no peer-reviewed study had examined the effects on restoration plans for the downstream Florida Everglades, which are supposed to get water from Lake Okeechobee, near the mine site.

She sent some of the emails to commissioners’ private email addresses. She signed one of them “Deep Rock Pit” — a joke, she said later, alluding to Deep Throat, the secret Washington Post source during the Watergate scandal.

County staff members issued notices of violation against Lake Point.

In 2013, Lake Point sued the county, the water management district and Ms. Hurchalla, claiming she waged an unlawful campaign against the company that cost it its plans to make money off its cleaned lake water.

The court agreed: The litigation found that commissioners conducted public business using their private email and delayed production of those emails — or destroyed them altogether — in violation of public records laws. Three commissioners were charged in criminal court. A jury acquitted one of them in April, and the state attorney dropped the charges against the other two last month.