By Isabella Biedenharn
Updated March 12, 2015 at 12:00 PM EDT
Casie Zalud

In the captivatingly creepy new book American Ghost, author Hannah Nordhaus discovers that her great-great-grandmother, Julia Staab, is New Mexico’s most famous ghost, haunting a Santa Fe hotel called La Posada. Backed by an army of psychics and ghosthunters, a crumbling family diary, and a frontier-sized heap of curiosity, Nordhaus sets out to discover who Julia was—and why her spirit has stuck around for all these years.

EW talked to Nordhaus about using psychics and mediums, and how to tell if a ghost is trying to get in touch with you from the world beyond.

ENTERTAINMENT WEEKLY: When you started this project, what were you most afraid of?

HANNAH NORDHAUS: I guess two things. The first was not finding anything. I knew that there was some documentation of my family’s history in New Mexico, but I didn’t know if I’d find anything about Julia. And then I was definitely afraid of having an encounter with Julia’s ghost. The nights I spent in the haunted hotel, I did not sleep very well. As much as I waffle in the book about whether I believe or not—I’m scared of ghosts.

Do you have a favorite Julia ghost story?

My cousin grew up in Santa Fe, and she told me a story I never forgot. She was friends with the hotel’s bartenders, and they told her about a new bride who was staying at the hotel. When the bride came in, Julia started flinging glasses at her head. A lot of people have also said that when they slept in her room, Julia would rip the sheets off of them. I think that’s the one that freaks me out the most.

That’s scary! You worked with a lot of psychics. How did you find a reputable one?

It was a combination of word of mouth and just straight-up Googling. The phone psychic was completely random: I literally Googled “psychics, Colorado.” I have no idea why I felt they needed to be in Colorado, since it was a phone psychic. But I needed some sort of boundaries. Then there were two different psychic organizations, and one was the American Association of Psychics. It sounded very authoritative, so I went with that one. Then, honestly, I looked at price. And the one I chose was really pretty. She just looked sensible. She was young. She didn’t look like one of those crazy psychics with really frizzy hair and scarves.

So what’s the difference between a psychic and a medium?

There are psychic mediums. Mediums talk to the dead, but most people go in not wanting to talk to the dead. Most people go in wanting to know about themselves in some way: “Am I gonna get married? Am I gonna have money?”

Did you ever feel like you had given away too much when talking to a psychic?

Yeah. [Laughs] Because I’d get really into it. You just go along on the wave of this story. They’d say, “Did she lose a child?” “Yeah, she did lose a child.” And then I’d tell all the details. I had a hard time holding back.

But you kind of want them to be right.

Yeah, and you get invested. You want them to support your own theories.

How did your thoughts on mediums and psychics change as you wrote the book?

I wasn’t a believer—I thought it would be comic relief for the book, because it’s a pretty sad story. But when I met them, they really believed in what they did. And you can’t really sit in a room with someone for an hour, in such an intense environment, and not have some respect for them. I really did end up feeling quite warmly towards them. And the other thing, in terms of writing the book, I was going through all these dry, historical documents, trying to understand who Julia was. The psychics really provided flesh to the bones of her story. They would tell me things like she liked flowers, she had loved another man, how much she loved her children, and that she sat in her rocking chair. Even though it may have been in their minds, they helped make her real to me by filling in those gaps in the story.

More than one person said that Julia liked flowers?

Yes, most of them did. Smell is a huge thing for psychics: they all talked about smelling flowers. So it is sort of convincing that maybe Julia really did like flowers. On the other hand, most middle-aged, rich, Victorian women probably liked flowers.

In the book, you explain the different ways you might know a ghost is around: breezes, flashing lights, orbs. Did you find yourself reading into little things?

Not so much. When I was in the thick of it, certainly, every time I’d wake up in the middle of the night and feel a tickle or something, I’d think, “That’s Julia! That’s Julia!”

In the hotel, or just in your life?

No, in my life. The psychics kept telling me if I opened myself up to her, she’d come to me in my dreams. It’s weird, I dreamed not so much about her, but about everybody else in her family. I was very, very hyper-aware for a while. And now life goes on—as you can tell from the book, I’m not the most sensitive person in terms of psychic stuff. I tried really hard to open myself up for a really long time, and now I’ve gone back to being the insensitive person that I am.

Do you think the facts you discovered while researching Julia’s life will change the legend in any way?

I don’t think they will. The story’s gotten farther and farther from the truth as it’s grown on the internet, but with a few time lapses and things that aren’t quite right chronologically, it’s basically true. I actually thought I would disprove a lot more of the story than I did.

If the hotel were torn down, what would happen to Julia’s ghost?

It would probably still be there. I found a dowser—who uses a divining rod to answer questions about the world beyond—through my massage therapist, who had a bunch of ghosts in his house. His house was fairly new, but it’s allegedly built on a Ute Indian burial ground, so there were Indian spirits, and then spirits of some miners. Judith the dowser came in and freed them, sent them away. But I talked to him recently, and he said that some of them are back. He needs to get Judith back in there.