'American Horror Story: Hotel' 's Ten Commandments Killer Speaks! 'I Was Like, "So Where Do We Go from Here?" '

"I definitely had a lot of conversations I had to be cagey about," says the AHS star whose character was revealed on Wednesday

Wednesday night’s reveal of the Ten Commandments Killer on American Horror Story: Hotel was quick, but it certainly wasn’t painless.

Spoiler warning: If you haven’t watched the most recent episode of AHS: Hotel, key plot details will be revealed ahead. For those who have seen the episode, keep reading for insights from the star who was revealed to be behind the Seven-style murder spree at the center of AHS‘s fifth season.

Early into the latest episode, weeks of speculation proved true when viewers learned that the very man investigating the show’s Biblically inspired homicides is also the one who’s been perpetrating them. That’s right: John Lowe is the Ten Commandments Killer!

Wes Bentley, who plays the beleaguered detective, talked with PEOPLE about the relief he’s feeling now that his character (and viewers) finally have “clarity” about the story behind John’s descent into serial killing.

In the past few months, “I definitely had a lot of conversations I had to be cagey about,” the actor tells PEOPLE, adding that he even had to keep his own brother in the dark!

Bentley, 37, says show creator Ryan Murphy told him about John’s twisted journey under strictest confidence while they were talking through the first few scripts.

Still, when the killer’s identity remained obscured week after week, Bentley recalls with a laugh: “I starting to think maybe Ryan was messing with me. I wondered, ‘Maybe I’m not the guy? Or maybe he said that to me to cause something to happen?’ But in the end I’m glad he told me.”

Blood-spattered killer or no, John’s struggles with alcoholism resonated with Bentley’s own history of substance abuse, which nearly destroyed his acting career before he hit rock bottom in 2009 and resolved to get sober.

Bentley says John’s horrific acts while blackout drunk feel “very close to the real thing [I experienced] – obviously not the killing or anything like that, but the change in personality and the sort of not knowing yourself and being surprised as John is in this moment of who he has been.”

While Bentley, who has admittedly played his fair share of “creepy, shady” characters, grounded his performance in John’s humanity, his character’s battle with addiction struck a deep chord: “He doesn’t even know himself, no one else can recognize him, [and he shows] the lengths you go and how you change when you’re on something. I’ve enjoyed [embodying] it in this setting because it’s honest.”

Bentley – who has a 5-year-old son, Charles, and an 18-month-old daughter, Brooklyn, with wife Jacqui Swedberg – also related to John’s motivation as a father of two young children.

“[Getting into John’s mindset as a parent] was easy. Part of what Ryan and I did talk about initially was that we fear both have about our children, the fear of losing them or something happening to them or you’re out of control: How would that change you? What would you do? Would it be surprising, the length to which you’d go? And I said, ‘I would do anything.’ When it comes to your kids, you kind of lose your mind a little bit protecting them and looking out for them and trying to keep them.”

With four episodes until it’s time to check out of this Hotel, John’s unique position – simultaneously self-aware and off-the-rails – made Bentley, whose own story has played out very differently from his character’s, seriously curious about what’s next.

“I was like, ‘So where do we go from here?’ ” he says. “And what they come up with is really great. I’ve been pleased with that because it’s also another side I get to explore further in John rather than him just being confused who he is.”

Then he adds with a laugh, “That said, just because you know who you are, that doesn’t mean it’s a good thing.”

American Horror Story: Hotel airs Wednesdays (10 p.m. ET) on FX.