Mr. Serpico’s plan had been a simple one — to keep his property wild and leave it to a preservation group upon his death, possibly for use as a retreat for other whistle-blowing police officers. But his plans were upended after Mr. Palladino bought a wooded parcel next to his and bulldozed much of it to put up a luxury home.

The 4.8-acre parcel abuts a favorite section of Mr. Serpico’s land where he often watched hundreds of swallows on a sandy bank, and where he walked a stream that runs partly through his property, looking for medicinal herbs.

Mr. Serpico said he had passed on an opportunity to buy the property for a low price years ago, because he thought it was environmentally protected from development.

But after Mr. Palladino, 58, bought the land in 2010, he started clear-cutting trees to build a luxury home to sell.

The chain saws and bulldozers disrupted his idyll, but Mr. Serpico said he was even more aggrieved by what he said was an intrusion by Mr. Palladino onto his property and upon nature. He has accused the builder of knocking down trees Mr. Serpico owns, destroying part of the swallows’ nesting area and being insensitive to the wild feel of the area.

In escalating hostilities, the two have traded insults and called each other trespassers. Mr. Serpico said he had been unable to get help so far from various government agencies and preservation groups.

Mr. Serpico said his predicament brought him back to when he was an idealistic young officer turned bitter and disillusioned after Police Department and City Hall officials ignored for a time his reports of rampant corruption. Eventually, his revelations led to the formation of the Knapp Commission and one of the department’s biggest shake-ups.