Have you ever investigated a murder in your partner’s family? If it happens to come up, take my advice: think carefully before accepting the case.

I have experience here. I’ve spent the last 18 months making a podcast about the murder of my wife’s great-grandmother, Dr. Naomi Dancy, in 1937. The problem is, while researching this, I found out that the murderer may have been her husband, John Dancy, my wife’s great-grandfather. Needless to say, this has not gone down well with my wife’s family.

They’re my family, too, but they can be pretty intimidating. My father-in-law, Jonathan Dancy, is a world-renowned philosopher; my brother-in-law is the Law & Order actor Hugh Dancy.

So why am I doing something that’s guaranteed to make them extremely angry? Well, because of a ghost. More specifically, because I think their murdered ancestor might be haunting my childhood bedroom.

Let me explain.

It all started in London a couple of years ago, when a woman noticed a stranger standing in her driveway. He was looking up at her house. When she approached him, the stranger told her that he had lived there some years before. “Do you still have that ghost in the top bedroom?” he asked.

Portrait of John Dancy, by Frank Cadogan Cowper.

As it was later reported to me, the woman went white. Her daughter had been telling her for years that there was a ghost in her bedroom on the top floor of the house, but the woman had always dismissed it. And yet here was this stranger saying his family had seen a ghost up there, too.

I tell this story because before the woman, or the stranger, lived in that house, it was my family home. I slept in that bedroom on the top floor as a teenager, and odd things used to happen to me there as well.

“Do you still have that ghost in the top bedroom?”

There was a vase that seemed to move around the room of its own accord, lights that would switch themselves on and off, a kind of indescribable chill that didn’t feel like a draft. I didn’t pay it too much attention. I explained the vase away as my sister trying to prank me, and the flickering lights and strange chill as the by-product of an old Victorian house. When my family finally moved away, I didn’t think about it again.

That was until, many years later, a series of odd coincidences led me to hear the story of that chance encounter in the driveway. I was now one of three people, none of whom knew any of the others, who had reported inexplicable experiences on the top floor of that house. I don’t believe in ghosts, but this was hard to ignore.

John and Naomi Dancy

And there was something else: the girl who most recently occupied the haunted bedroom said that the ghost she saw at night was a faceless woman. Which is where we get to the second extraordinary coincidence in this story.

Eighty-three years earlier, my wife’s great-grandmother Dr. Naomi Dancy was murdered in the house right next door, by two gunshots to the face. Naomi’s murder captivated Britain for a brief spell in the late 1930s. She was a beautiful and groundbreaking doctor who had been brutally murdered in her own bed.

It was supposed that her brother, a half-blind soldier suffering from shell shock in World War I, had killed her and then killed himself. But the shell-shocked brother wasn’t the only other person in the house on the night of Naomi’s murder. Her husband, John Dancy, was there, too.

Dancy was a swashbuckling figure revered by my in-laws. He was a beachfront boxer, a cabaret performer, a songwriter, a magician, and a hero of the war. Or at least that’s the story he told them.

Our investigation found so many lies that the real story of his life—and the murder—was blown wide open. Was the murder-suicide actually a double murder committed by the beloved family patriarch, John? This is not a question that goes over well at family gatherings.

So here I am, trying to figure out if my childhood bedroom is haunted, if that ghost might be my wife’s great-grandmother, and if she’s hanging around this realm because she needs someone—me—to find out the truth of what happened more than 80 years ago.

Tristan Redman is a journalist for Al Jazeera who lives in Paris. Ghost Story will be released on October 23