Former Disney kid Ross Lynch (right) plays the boy who would become the serial killer and cannibal Jeffrey Dahmer in My Friend Dahmer . Alex Wolff plays Dahmer's friend Derf, who wrote a graphic memoir about his former classmate..

The final panel in John "Derf" Backderf's chilling graphic memoir, My Friend Dahmer, is a haunting portrait of the author after getting a call from his wife, a reporter in Akron, Ohio, that his high school friend had been identified as a serial killer and cannibal who had murdered 17 people, eating some of their body parts.

What was Derf thinking at that moment?

"I don’t think I had any thoughts," he wrote in an email interview from Amsterdam. "It was just total shock, followed by weeks of absolute surrealism.

"I remember a week or so after his arrest, I was standing in the checkout line at a grocery store in Cleveland, where I live. I glanced over at the magazine display and every ... single ... cover had a photo of Dahmer staring out at me. This was a guy I sat next to in study hall and gave rides home from school! I just left my cart and bolted out of the store. It was too much for me."

That moment was also the beginning of a 26-year odyssey into the mind of his classmate at Revere High School in northeast Ohio. They grew up in the 1970s in Bath, Ohio, a suburb of Akron that is the definition of the cliche "bucolic." Bath borders the 33,000-acre Cuyahoga Valley National Forest; it's so pricey now that Lebron James lives there.

Derf produced two shorter versions of the book before the international best-seller was published in 2012. The movie adapted from the memoir opens Friday in Phoenix. Former Disney star Ross Lynch plays the serial killer. Alex Wolff portrays Derf.

Full disclosure: Derf, his wife, Sheryl Harris; my wife, Deb Van Tassel, and I all worked at the Akron Beacon Journal in the 1990s and were members of the team that won the Pulitzer Gold Medal for Public Service for our examination of race relations in the city. Derf, who worked part-time as an artist, was off the day in July 1991 that he got the call from Sheryl about his friend Dahmer.

Phoenix New Times readers will remember Derf from his satirical, provocative cartoon strip "The City," which ran in New Times and more than 100 other alternative papers for more than a decade beginning in the '90s.

I caught up with Dahmer's old friend via email last week to chat about the experience. Some of the questions and answers have been edited for length.

Phoenix New Times: You’ve done a deep investigative dive into one of the most complicated, notorious minds in history and spent parts of the past quarter-century there. How scary has it been?

Derf: Y’know, the book took so long to finish, 20 years, that it became more about process than about getting inside Jeff’s head. ... Not that there weren’t emotional hurdles. Remember, my entire personal history changed in an instant in 1991. Everything was redefined in a completely sinister way. That was a very disorienting experience and took some time to come to terms with. Once I started working in earnest on the book, however, I shoved all the emotional stuff aside and just concentrated on the nuts and bolts of making comics, figuring out how to compose scenes, and concentrating on details. That’s fun for me. So it wasn’t really as scary as you would think.

What was it like to see yourself portrayed on screen for the first time?

Honestly, I didn’t have much of a reaction. I guess I was mentally prepared. I spent some time on the set. The actors were all calling themselves by their film names, so Alex Wolff went by “Derf” and Ross Lynch answered to “Jeff.” That was a bit of a head-shaker, especially since Ross looked so much like Dahmer when he was in costume. One time in particular, I was chatting with Ross between scenes when he was in his full Dahmer get-up, and it freaked me out. I said, “Dude, you HAVE to take off those glasses or I can’t talk to you.” Ross tells that story often.

For our readers who remember you from "The City" … what will surprise them about the book and the movie?

My Friend Dahmer is very dark and delivers an emotional punch to the gut. The artwork has rich detail that simply isn’t possible in a small comic strip. Most people who knew me from the crazed humor of "The City" are astounded I had something like this in me, which makes me smile. It’s always fun to be underestimated! It’s not just MFD. I’ve done three books since 2010, all of which are better than anything I did in comic strip form. It’s been a total reboot. It’s an incredible gift, to become an overnight sensation after 30 years working. My life is a dream now, traveling the world, making movies. I mean, just look at this week. My film opens, I’m getting write-ups in Rolling Stone and Vanity Fair, and I’m typing this interview in a cafe in Amsterdam! How the hell did this happen?

During a class trip to Washington, Dahmer conned his way into the office of Vice President Walter Mondale and showed a human side of himself that few of us might expect to see. Do you think it was because he was away from his difficult home life? Any other moments like trip that you remember?

There were a few, but they became rarer and rarer as high school wore on. That incident in D.C. was probably his last flash of “normality.” There wasn’t much left of him by our senior year. I wouldn’t pin his fate on what happened at home. Hell, lots of kids had parents who went through nasty divorces and none of them went on to kill 17 people. What his parents' breakup provided was cover. They were too wrapped up in their nuclear divorce to notice what was happening with Jeff. But the teachers and school officials were no better. That still astounds me, because he was completely out of control and it was so apparent to us kids.

A couple of years after Dahmer's arrest, an Akron reporter found an article from the 1960s detailing how a woman was arrested after driving erratically after midnight. She said she was chasing aliens. She had her two sons in the back of the car. She was Joyce Dahmer. No real question here, except: Does that surprise you?

No, I was well aware of that story. One of the Dahmers' neighbors was a kid in our class and saw Joyce that night, pointing at the sky and yelling about spaceships, and he dutifully spread it all over school the next day. It was a small town. Stuff like that spread. I heard the rumors about her problems and knew she had been in a mental hospital.

That stuff has been overblown, frankly. Yes, she had some issues with mental health, but she wasn’t just some crazed loon. I remember her as a nice lady. Joyce was demonized as the cause of Jeff’s madness, mostly by Lionel, her ex-husband. ... I think it’s ridiculous to pin blame solely on her. ... She wasn’t the greatest parent to be sure, but she wasn’t a villain. She was a tragic figure who had a very unhappy life.

In a deeply sad way, the book seems to be so much about the value of friendship.

I don’t think it’s a coincidence that when high school ended, Jeff became a monster. He had lost whatever friends he had when we all graduated. He was utterly alone at that point, with only the voices pounding inside his skull.

Certainly a big part of the story is the way teenage friendships play out. That’s why it resonates with people. It’s all too familiar, that sort of casual cruelty and indifference. I don’t spare any punches there, which is how you have to approach memoir, with brutal honesty. You can’t be afraid to make yourself look like an asshole.

Mostly, however, I think My Friend Dahmer is a book about failure. Everybody fails; Jeff’s parents, the teachers and school administrators, the cops, Jeff’s friends, Jeff himself.

Looking back 40 years later, was there a time when you should have been afraid of Dahmer when you were all teens?

Obviously. The hardest part to deal with for me was how close my friends and I were to that first murder (in 1978), mere yards away from the body at some points. If the situation had been different, yeah, that could have been me chopped up in the trunk of Dahmer’s car. That first murder was a crime of opportunity. Dahmer simply lost control for a second, and Stephen Hicks was dead. That’s all it took.

The day he carved up the body, we were all just down the hill at a house party at [another high school friend] Neil’s. I’ve no doubt we were imitating some of Dahmer’s schtick, because it was part of our everyday banter at that time. And 100 yards away, Jeff was butchering a corpse. I had a few sleepless nights over that.