An elderly Pennsylvania couple -- infamous for their personal crusade against alleged "transmissions" from a nearby pharmaceutical plant -- was found dead by a U.S. postal worker outside their home on Tuesday, officials said.

The bodies of Ross Woodward, 84, and Rhoda Woodward, 81, were discovered outside their Whitemarsh Township home at about 11 a.m. Tuesday, the Montgomery County District Attorney’s Office said.

The Woodwards’ cause of death has not been released pending toxicology results. Officials said they conducted autopsies on Wednesday.

Authorities have not released much information about the couple’s mysterious death. Neighbors told the Philadelphia Inquirer the couple was known in the community for their personal war with McNeil Consumer Healthcare, a pharmaceutical manufacturer that has a plant about a mile away from their home.

Ross Woodward claimed the company’s plant produced tremors, or what he described as “transmissions,” in the ground under his home that kept him awake at night, neighbors said. His house had a visible sign that read “Happy Transmission.”

The 84-year-old, seemingly fed up with the vibrations, threatened the facility’s staff, leading to yearly harassment charges from 2014 to 2017, the newspaper reported.

He pleaded guilty to four harassment charges and paid fines amounting to hundreds of dollars.

Neighbors said the couple was in poor health at the time of their deaths. Rhoda suffered from Parkinson’s disease, while Ross had heart and pancreatic issues.

Others told FOX29 the Woodwards lived in the town for decades and had two children.