Directed and executive produced by Susanne Bier and created and written for television by David E. Kelley, who also serves as showrunner, the HBO limited series The Undoing follows Grace (Nicole Kidman) and Jonathan Fraser (Hugh Grant), a couple with a seemingly perfect life until the revelation of secrets and lies threatens to undo it all. When a violent death changes everything, Grace must figure out what that means for her family and how to pick up the pieces.

During this 1-on-1 interview with Collider, Édgar Ramírez, who plays NYPD Detective Joe Mendoza, talked about the experience he had when reading these scripts, what he liked about his character, how his background as a journalist informs his approach to the roles that he plays, whether we can ever really know somebody’s truth, and even wondering whether his own character could be involved in the mystery of it all.

COLLIDER: When this project came your way, what were you told about it? Did you know much about it when you started reading it, or did you get to experience those reveals the same way that the viewers do?

EDGAR RAMIREZ: I had a total reveal experience. When Nicole [Kidman] and Susanne Bier, our director, sent me the scripts, I had no idea. I knew that it was a love story gone wrong and that there was a crime but I didn’t know much. I was actually discovering everything as I was reading, and I couldn’t stop. I had to read all of the episodes.

What did you like about your character? Were there things about him that you found most interesting?

RAMIREZ: I’m very inquisitive. I’m a journalist. That’s what I did before I became an actor, so I relate to the inquisitive element that my character Joe Mendoza has, along with the obsession with searching for the truth. In the end, we’ll never find out the truth but what we try to do in our lives is to find it. The truth is not a static, flat thing and it’s not a picture. Especially when we deal with human emotions, we do it with the human experience. It’s more of a sphere that has different faces. While one is being hit by light, the other one stays in the shadows and keeps moving. That is something that we find in this story, not only related to the crime that takes place but it also has to do with the characters trying to find out if they really know everything they think they knew about the people that are closest to them. The show somehow places the question, do we really know the people that are closest to us? Do we know all of their truths? Should we know their truths? Are we ever gonna know somebody’s truths completely? That, for me, was fascinating. My character is the objective eye that’s there trying to make sense out of this puzzle but he’s also sucked into another search that goes beyond the professional seeking of the truth, as a police officer. He gets sucked into the sexual energy and the complications of the drama that he’s investigating.

Do you feel like your background as a journalist informs how you approach all of your characters? Does it influence the way you dig into them before you play somebody?

RAMIREZ: Yeah, absolutely. I love to research and I have a very journalistic approach to my characters. Whether they’re based on real people or fictional, I always try to go and talk to, for example, real NYPD detectives. I went to two police precincts in New York and was lucky enough to talk to real NYPD detectives that shared their experience and knowledge with me. And Michael Devine, the wonderful actor that plays my partner in the show, happens to be a real police detective. He’s a third-generation police officer in New York, and I was very lucky to have him on my side, sharing his experience and expertise. I always try to somehow find myself in the characters that I’m playing, in order to then transcend my personal limits and limitations to portray the character. If it’s a real-life person, then not only do I try to document myself, as much as I can, with that character but I try to track his family down, his lovers, and people that were close to him, that would give me a different perspective and point of view. I always try to do that. That is the way you normally approach stories. I was an investigative journalist, and that’s what I did. I look for more angles. If you look at one thing but you look at it from different angles, you’re gonna see something completely different, even though you’re looking at the same thing. That’s how I try to approach my characters.

What surprised you about this script?

RAMIREZ: It was very sexy. It’s a very sexy story. It’s an adult drama and adult thriller that reminds me of the great adult thrillers from the ‘80s and ‘90s, where interesting things happen to interesting people and complicated things happen, and the sexual energies complicate things even more. Those stories don’t get made very they’re very often, lately. I thought the characters were so well written. They were so full of contradictions. I remember, at the beginning of my reading of all the episodes, there was a moment where I even thought, “Is my character gonna be involved in this? Is he in on it?” When that happens, you can expect anything and it could go anywhere. That was great. I knew from page 10 that I wanted to do it.

And you keep going back and forth on who might have actually done this, throughout the series.

RAMIREZ: Yeah, and that’s great storytelling. David E. Kelley is such an amazing writer. He’s so sensitive and so smart. He understands human nature and the human experience so well that he was able to create these characters that will make you suspicious. They will make you doubt everyone. The person that you least expect, suddenly makes you say, “What? Is it possible?” I thought, “If my character ends up being involved in this, I wouldn’t be surprised.” That’s great when you have that opportunity.

You can never fully rule any of the characters out.

RAMIREZ: Exactly. I discussed that with the detectives that I spoke to. I presented the case to them, with all of the different elements, because I wanted to hear what they would say. They said, “When you rule someone out very easily, just keep it there, very close to you, because you may come back to that person again. Sometimes the whole thing is designed for some people to be ruled out right away.”

The Undoing airs on Sunday nights on HBO at 9/8c.

Christina Radish is a Senior Reporter of Film, TV, and Theme Parks for Collider. You can follow her on Twitter @ChristinaRadish.