SPRING HILL, Fla. (WFLA) – A grisly discovery in Florida on Tuesday may change the course of a decades-old serial killer case.

Human remains were found in the yard of a Hernando County house belonging to the family of convicted serial killer William “Billy” Mansfield. Neighbors say multiple investigators began showing up at dawn, bringing bulldozers with them to facilitate the sobering task of digging for bodies.

Graphic discoveries have been unearthed there before. According to court documents and dozens of detectives, what happened in the Spring Hill home over the years was the stuff of nightmares with details so horrific and so evil, longtime residents admit just talking about the home makes them uneasy.

Mansfield’s father and brother both remain in the house, both with lengthy criminal histories. In fact, Billy’s brother, Gary, was arrested on drug charges in the early-morning hours Tuesday.

That’s when the case broke wide open, sources say, with Gary sharing the secrets of the past with deputies.

Witnesses say as he was being escorted from the home by deputies, he began yelling loudly, demanding immunity on the impending drug charges. Gary tipped off detectives with a clue that launched the new investigation, yelling that there are bodies all over the property.

The home where the remains were found is no stranger to law enforcement. Graphic discoveries have been unearthed there before, bringing with it the story of what neighbors call a house of horrors.

According to court documents and dozens of detectives over the years, what happened in the Spring Hill home was the stuff of nightmares with details longtime residents admit just talking about makes them uneasy.

This property has been tied to murders, rape and heavy drug use from occupants inside, including a twice-convicted child molester, according to neighbors.

Prosecutors say Mansfield frequently tortured women he kidnapped inside the home.

Mansfield fulfilled a sick and twisted fantasy with his father and brother, presenting them with young women who were bound and gagged, but still alive, prosecutors said.

The family members sexually assaulted and tortured the victims in the last moments of their lives before Billy murdered the women, often dismembering them in the house, court documents allege.

Then, to satisfy his growing obsession, Billy would bury the bodies nearby, admitting years later in court that he wanted them close.

Forensic teams were at the home from sunup to sundown on Tuesday and were back again on Wednesday.

The newly-found remains now have detectives searching for answers.

What exactly took place on the secluded property? What happened behind closed doors in the family home of this convicted killer, now serving four life sentences in a California prison?

Are there more bodies of victims buried deep in the land surrounding the home? And, if so, who are they? Were they reported missing years ago when the crimes were carried out in the late 1970s?

Billy Mansfield is serving life in prison after murdering four Florida women and a California woman he met during a trip with his brother.

The grisly crimes are chronicled on websites like Serial Dispatches, documenting the details of the murders, subsequent arrests and multiple life sentences. Prosecutors were originally pursuing the death penalty in Florida, and that’s what made Billy Mansfield confess, plead guilty and head to prison for the rest of his life.

The family compound still has neighborhood residents visibly nervous as they talk about Tuesday’s discovery.

“That family is dangerous. They will kill you, like they killed others. I can’t say anything about them at all. I might get killed. They’re crazy,” said a man who did not want to give his name.

After Billy carried out his vicious crime spree, killing multiple women between 1975 and 1980, the case is once again drawing attention more than 40 years later.

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