Even though Tess Gerritsen has written 30 novels, including multiple best-sellers and a mystery series that inspired the long-running TV show “Rizzoli & Isles,” the Camden author is always looking for new ways to tell stories.

Finding partners in crime has helped with that.

“Choose Me,” a murder mystery that centers on a reckless affair between a college professor and a student, is Gerritsen’s first collaboration with another author. The book, out this month, includes chapters from female characters’ perspectives, written by Gerritsen, and chapters written through the eyes of male characters, penned by mystery writer Gary Braver. The pair will describe how they wrote the book – which Gerritsen says took twice as long as her solo projects – during a virtual author talk Thursday organized by the Portland Public Library.

Another try at a new type of storytelling – and another collaboration – has resulted in the documentary film “Magnificent Beast,” about the long and storied relationship between pigs and humans, which Gerritsen made with her filmmaker/photographer son, Josh Gerritsen. The documentary is being shopped to film festivals, and the Gerritsens have an agreement with PBS to make the film available to public TV stations around the country beginning this fall. They also collaborated in 2016 on an indie horror film made in the midcoast region called “Island Zero.”

STARTING WITH A QUESTION

Gerritsen, 68, traveled around the world with her son to make “Magnificent Beast.” Her role was researcher and interviewer. She’s seen on camera talking to anthropologists, scientists, pig hunters, farmers and pig owners. She also narrates the film.

The research part was easy, as she does tons of that for her books, including medical and police research for her Rizzoli & Isles series, about a Boston police officer teamed with a medical examiner. The interviewing took a little more time to get used to, but in the end, it all came down to her asking questions to solve what was a mystery in Gerritsen’s mind: Why do some religions forbid the eating of pork, and why are pigs so often used as examples of something dirty or disgusting?

“It’s just another form of storytelling, and it’s just another form of a mystery. It was a question I was trying to answer,” said Gerritsen.

The writing of “Choose Me” began with a question too, she says. It was a few years ago, when the #MeToo movement was taking hold and several male celebrities were being accused of sexual harassment and assault. The movement made Gerritsen think about the different ways men and women might see something, including a relationship they were both in. She asked herself, what if a mystery story focusing on an affair or a crime was written from two different perspectives – with a woman writing the female character’s point of view and a man writing from the male character’s vantage?

She approached her longtime friend Gary Goshgarian, who writes under the name Gary Braver. He’s also an English professor who teaches writing at Northeastern University in Boston. They came up with a story about a young woman attending college who is found dead, after having an affair with a married professor.

Publicity for the book describes Taryn Moore as a brilliant college senior “who is desperate for love and will do anything to get it” and Jack Dorian as a popular professor who “feels neglected by his busy doctor wife.” When police detective Frankie Loomis investigates Moore’s death and discovers the affair she becomes “certain Jack is a liar, but is he a killer?” read a publicity blurb for the book.

The book is not about the #MeToo movement, Gerritsen said, but instead is a story about the complexities of people’s characters, actions and views.

“It’s about how everybody makes mistakes. Some might destroy us and some we desperately try to atone for,” Gerritsen said. She added that while many of her police mysteries have a “clear-cut hero,” this book does not.

To write the book, Gerritsen and Goshgarian each started writing alternating chapters, in chronological order. Gerritsen wrote chapters that were from the viewpoint or in the voice of the dead college student, Moore, or the female police detective, Loomis; Goshgarian wrote chapters from the eyes of the male characters, including the college professor, Dorian.

“I think Gary had the more difficult part, writing about this man who betrayed his marital vows and his teacher’s vows. How do you make a character like that likable?” said Gerritsen. Goshgarian said he wanted the character of the professor to be realistic and wanted his writing to “neither vilify nor exonerate him.”

Goshgarian says he was excited to work with Gerritsen, who has worldwide popularity and a huge audience for her books. He said his biggest challenge was trying to make his writing style mesh with hers.

“I had to kind of edit myself as if I were Tess. Her style is direct and incisive, where I tend to telescope the moment and ruminate more,” said Goshgarian, 78, who lives in Arlington, Massachusetts.

The two authors say they had to know each other’s characters well, since they show up in each other’s chapters. So while Goshgarian wrote chapters from the professor’s point of view, Gerritsen would write about him too in the chapters where the female police detective is questioning him in connection to the murder. Because of the back and forth, with each author reading and studying each other’s work, the book took about twice as long as one of Gerritsen’s solo ventures, she said.

Though they wrote it chronologically, the book’s editor really liked Gerritsen’s police detective character and wanted her chapters moved up. So after some rearranging, the book now starts with the discovery of Taryn’s death and the police investigation.

“It turned into a book where you see both the crime being investigated and how it happened,” said Gerritsen. “The real challenge is to keep the audience from knowing all the answers.”

FINDING ANSWERS

Gerritsen grew up in San Diego in a Chinese-American family. Her father was a Chinese-American who cooked in a restaurant and her mother was a social worker who was sent to the United States from China by her parents when the Communists took control of the country after World War II.

Her parents wanted her to study hard and gain a secure profession, so she went to medical school and became a doctor. It was in medical school at the University of California, San Francisco that she met her husband, Jacob Gerritsen, who also became a doctor.

She practiced medicine for about five years before taking some time off to care for her two young sons. It was then that she first explored her passion for writing and published her first novel, “Call After Midnight,” in 1987. She and her husband moved to Maine in the early 1990s, to Camden, and she continued to pursue writing. Her reputation became established with her first medical thriller, “Harvest,” in 1996, which made The New York Times best-sellers list.

She’s written 12 novels about homicide detective Jane Rizzoli and medical examiner Maura Isles, which inspired the eponymous TNT television series starring Angie Harmon and Sasha Alexander. The show ran from 2010 to 2016 and is still available on streaming services. Her books have sold more than 40 million copies and been published in 40 countries.

It was while on a book tour in Turkey a few years ago that Gerritsen first got the idea to do a film about pigs. She had a hankering for bacon while on tour, but found it was scarce, because of the Muslim taboo on eating pork. Growing up in a Chinese household where the family “ate everything,” Gerritsen started to wonder about the taboo, about why there are restrictions in both the Muslim and Jewish religions against eating pork.

She thought about writing a book about various taboos against eating all different animals – horses, dogs, pigs. But her son, Josh Gerritsen, a professional photographer and filmmaker who lives in nearby Lincolnville and has raised pigs on his farm, thought a film specifically about pigs would resonate with people. The English language and American culture uses pigs as a negative image, Gerritsen said, to denote someone dirty or disgusting in some way.

“We realized that the story got down to the character of the pig itself. What is it about pigs that put us in conflict with them?” said Gerritsen. “So we explored this shared history we have with pigs.”

The Gerritsens found pigs to be smart and cunning, behaving like spoiled pets when circumstances allowed and evolving into successful feral animals terrorizing farmers around the country. Josh Gerritsen said he saw video taken by farmers of pigs entering a corral trap – to eat the bait food – with one pig staying outside as a lookout, to signal the other pigs to run if there was a sign of trouble.

“We found they could be sweet and kind. But we met some pig owners whose pigs got more and more demanding, the more things they got. We met with pig owners and saw how the pigs behaved, how they didn’t want us coming in taking attention from them,” said Josh Gerritsen, 36. “We asked pig owners, who also have dogs, which were smarter – their pigs or their dogs? They all said their pigs.”

After working on two films with his mother, Josh Gerritsen said a key to their collaborations is a shared aesthetic and a shared view of what the film should be. They both wanted “Magnificent Beast” to be light-hearted “with a lot of soul” but to treat the film’s “maligned subject with the seriousness it deserves.” The two were co-directors and co-producers on the film.

Tess Gerritsen continues to write her own books and has another Rizzoli & Isles volume due out next year. Josh Gerritsen is a selectman in Lincolnville and is currently working on a film about the conversion of a Maine paper mill into a facility for making building insulation out of wood fiber.

But mother and son say they will continue to work together on films. One idea they are considering is another horror movie, inspired by Tess Gerritsen’s 1998 novel “Bloodstream.” It’s a medical thriller about a small-town doctor racing to stop a violent epidemic. Josh Gerritsen said there are lessons they both learned while filming “Island Zero” that they could apply to another horror film.

“I think we work together so well because I’m technologically inept, and he’s been going everywhere with a camera on his shoulder since he was 14,” Tess Gerritsen said. “What I love about making films is the storytelling.”