A South Portland man recently had his first novel published. No, make that his first thriller. A riveting, suspenseful thriller. A genuine page-turner.

But having a book in print doesn’t separate Regan Ashbaugh from thousands of other published writers, ranging from John Grisham and Stephen King to the vanity-press wannabes. It’s what Ashbaugh wants to do with the proceeds from his novel that makes him different.

Ashbaugh’s dream is to make the Southern Maine Autism Resource Center a reality. Autism is a lifelong developmental disability, and autistic children have problems in communication, learning and social interaction. They often live in their own little world.

Ashbaugh’s 7 1/2-year-old son, Trevor, has the neurological disorder, as do about 1,500 other people in Maine. Ashbaugh and his wife, Nancy, quickly found out how scarce reliable medical information is about autism.

“Ask any parent of any autistic child and they will tell you that the medical community doesn’t know s— about this disorder,” said Ashbaugh at his South Portland home. “Our pediatrician never once mentioned the possibility of it. If you want information about autism, ask the parents instead.”

During the day, Ashbaugh, 40, is the Portland vice president for a national investment-banking firm. He serves on the boards of several charities. He’s also a volunteer firefighter in South Portland.

But at night, after Trevor and his 5 1/2-year-old brother, Lucas, have gone to bed, Ashbaugh climbs the stairs to a cubicle on his home’s third floor, where he explores the dark side of humanity. His crammed office is lined with reference materials, on topics ranging from buttons and butterflies to crime and punishment.

It’s here where he embraces his calling.

“I made a pact with God that if he would help me get the words out, I would use the proceeds to help other parents not to have to go through what we did,” Ashbaugh explained. “I believe strongly that I was put here for this purpose. That’s why the words come, why they’re as good as they are. That’s God working through me.”

Ashbaugh has been prolific. In less than four years, he has four books in various states of development. “Downtick,” which was rejected 36 times, was finally published as a paperback in April by Pocket Books, a division of industry giant Simon & Schuster. The powers that be at Pocket were impressed enough to contract for Ashbaugh’s next three books to be published in hardcover, with national promotion planned.

On this recent day, the Connecticut native was lighting up a celebratory cigar, after finishing the final rewrite of his second book, “In the Red.” Instead of his usual pinstriped suit, he’s dressed in a sportscoat, slacks and a dress shirt, in anticipation of a book-signing appearance later that afternoon. He has been busy with public appearances to promote both “Downtick” and the autism-center concept.

“Downtick,” a term for a downward movement in a stock’s price, tells the story of two old friends and Wall Street veterans who are stalked by a psychopath whom they had slighted years before.

Ashbaugh, who has been with the same investment banking firm since 1982, can relate to both the novel’s protagonists. Like David Johnson, he was career-driven for quite a few years. But like Jonah Roberts, he escaped New York for Maine 10 years ago, seeking a better quality of life.

The author does a masterful job of detailing various police agencies’ efforts to hunt down the elusive killer. That comes from hours and hours spent with police officers, especially Portland Detective Daniel Young.

“Downtick,” which spent 13 weeks on the Maine best-seller list compiled by the Portland Press Herald, has drawn its share of critical praise. Best-selling author Clive Cussler called it “masterfully crafted … a hard-to-put-down thriller you can’t help but enjoy.”

Ashbaugh writes every night, producing 2,000 to 2,500 words a session. Raised in a family with a strong work ethic, he says that he’s creating something for people who are contributing to the autism foundation.

“I get 56 cents from each book, and the reader gets hours of entertainment,” he said. “I figure that’s a fair trade. It’s a lot better than asking for money.”

His wife, Nancy, chief clinician on the child-care unit at South Portland’s Jackson Brook Institute, feared there was something wrong with Trevor when he hadn’t begun speaking by age 2. A Boston specialist diagnosed Trevor as autistic.

“That just devastated me,” Ashbaugh recalled.

Not that many years ago, an autistic child would be automatically institutionalized. Instead, the Ashbaughs sought and found early intervention for Trevor.

“We spent the equivalent of a very expensive college education to get Trevor early intervention,” he said. “At one time, we had a team of 13 people here working with him. Because of that, Trevor may be able to live more independently as an adult, maybe with one other person.”

Ashbaugh resolved to help others who find themselves in the same situation. So far, the Southern Maine Autism Resource Center is just an idea. Ashbaugh has spent $10,000 setting it up as a nonprofit corporation. He wants it to provide all kinds of services, including counseling, training and treatment, to autistic adults and children throughout the state, but it will take hundreds of thousands of dollars to get the center off the ground.

“You would not believe the letters I get,” he said. “This has touched the hearts of so many people because it’s such a lonely, isolating disorder. About 75 percent of marriages with autistic children end in divorce. So we’re hoping the center can be the glue that keeps families together. I have faith this will happen, because that’s why I’m here.”

His writing, and through that funding the foundation, has helped Ashbaugh to cope with Trevor’s autism as well.

“It’s a grief that doesn’t go away, but you learn to live with it,” he said. “Helping other people helps me, so it’s not entirely altruistic. I’ve come to terms with it. But lying in bed, reading to Trevor, I’ll still cry at times.”

Ashbaugh is thankful for the departmentalized team of people who review each manuscript and help him with research.

“All have gone above and beyond what would normally be expected of them,” he said. “They viscerally believe we were put here for this purpose.”

Next up from Ashbaugh will be “In the Red,” which will be published in January. Also with a Wall Street background, it’s a story about firefighters and an arson investigation, and is based in Manhattan, Connecticut, New York’s Westchester County and New Jersey. Ashbaugh said the book is more character-driven than “Downtick,” which was more plot-driven.

His third novel, “Take Down,” is written but not yet edited. It’s about the Federal Reserve, and is based half in Washington and half in Maine. He’s just begun writing “Naked,” about a serial killer who is killing brokers in Boston.

Ashbaugh enjoys being able to help others by doing an activity that he loves.

“I’ve just sat at my keyboard and laughed, because I’m doing something I love that much,” he said. “This is a catharsis beyond anything I have ever done. I have to write. It’s just like breathing to me.”

“Downtick” is available at Borders, Bookland and Waldenbooks. For more information about the Southern Maine Autism Resource Center, call Dianne Madison at 799-6388.