“The Watcher,” Netflix’s new nightmare-inducing limited series is horror creator Ryan Murphy’s latest spooky story brought to life. However, unlike “American Horror Story: Murder House,” a season from Murphy’s popular anthology horror series, this harrowing “haunted” house story is based on real-life events.

A dream home turned nightmare, The Watcher follows the story of the Brannock family, who are based off of the real life couple Derek and Maria Broaddus and their three children. The story begins shortly after the pair bought their dream home in Westfield, New Jersey: a gorgeous $1.3 million home—perfect for any growing family.

However, it wasn’t long before things took a dark turn for the Broadduses. In June 2014, just three days after the Broaddus family had purchased the home and had begun their renovations, a large white envelope made its way into their mailbox. Addressed in thick, clunky handwriting to, “The New Owner,” and signed by someone under the pseudonym, “The Watcher,” the letter read, “657 Boulevard has been the subject of my family for decades now and as it approaches its 110th birthday, I have been put in charge of watching and waiting for its second coming. My grandfather watched the house in the 1920s and my father watched in the 1960s. It is now my time. Do you know the history of the house? Do you know what lies within the walls of 657 Boulevard? Why are you here? I will find out.”

The letter became more and more threatening as it continued.

“I see that you have flooded 657 Boulevard with contractors so that you can destroy the house as it was supposed to be. Bad move. You don’t want to make 657 Boulevard unhappy…Was your old house too small for the growing family? Or was it greed to bring me your children? Once I know their names I will call to them and draw them too [sic] me.”

The Broadduses consulted the previous homeowners, John and Andrea Woods, and discovered that they too had received a strange letter from The Watcher, although theirs was significantly less threatening. The Woodses stated that shortly before they moved out, they received a letter in which someone claimed to have been keeping a vigilant eye over the house. However, this was the first and last letter they had received, so they assumed it was just a harmless prank.

The Broadduses were much less fortunate, as two weeks after the first letter, a second arrived, this one much more threatening than the first.

The Watcher described intimate details about the family, such as the make, model, and year of the family car, the Broaddus children’s nicknames, as well as their names and birth order, and types of renovations the Broadduses were completing. “All of the windows and doors in 657 Boulevard allow me to watch you and track you as you move through the house,” wrote The Watcher. “I pass by many times a day. 657 Boulevard is my job, my life, my obsession. And now you are too Braddus [sic] family”

Between the renovations and the creepy letters, the family decided to delay their official move-in to their new home Additionally, after the arrival of the second letter, they stopped bringing their children to the house. However, The Watcher seemed to become increasingly more anxious to see them do so. The Watcher wrote, “Where have you gone to? 657 Boulevard is missing you.” The Watcher questioned the family as to where the bedrooms would be when they began sleeping in the home, or where the children would play.

“Will the young blood play in the basement,” asked The Watcher, “Or are they too afraid to go down there alone? I would [be] very afraid if I were them. It is far away from the rest of the house. If you were upstairs you would never hear them scream.”

Eventually, the Broadduses decided that they could no longer inhabit the home. Upon completion of renovations, they listed the house on the market. When they were unable to find a buyer, they began renting the house. In February 2017, over two years since the arrival of the first letter, the Broadduses received the final letter from The Watcher, threatening revenge for the “harm” the Broadduses had done to the house.

“Maybe a car accident. Maybe a fire. Maybe something as simple as a mild illness that never seems to go away but makes you fell [sic] day after day after day after day. Maybe the mysterious death of a pet. Loved ones suddenly die. Planes and cars and bicycles crash. Bones break.”

Though no physical harm ever befell the Broadduses, the psychological harm was enough to prevent them from moving into their previously thought of dream home. The Watcher case has petrified and perplexed true crime fans for years, and now the story is scaring Netflix audiences as well.

However, perhaps the most bone-chilling fact from The Watcher case, is that despite lengthy investigations and years of wondering, The Watcher’s identity to this day is unknown.

The Watcher could still be watching.