Ausma Zehanat Khan is a Canadian author of crime and fantasy novels. While currently living in the U.S., the writer with a PhD in international human rights law still calls Toronto home. It's the city where her thriller A Dangerous Crossing is set.

The fourth instalment in her detective procedural series, the novel features Inspector Esa Khattak and Sergeant Rachel Getty who are caught up in a globetrotting mystery involving a missing woman, a double-murder and the Syrian refugee crisis.

Khan tells CBC Books how she wrote A Dangerous Crossing.

"Toronto is my hometown and the city is a key part of my book and who my detectives are. I come back to visit four to six times a year and I'm always discovering new things about it. It's a world-class, multicultural city with a lot to offer. Cities like that help to shape and create characters like Esa Khattak and Rachel Getty.

"It's not just geographical: There's an attitude or a sensibility from having lived in Toronto where you understand you're one of many different communities currently negotiating how to happily live together. It's a feeling I wanted to set as the baseline for the book series."

"It took me a year to write the book; I'm writing about the refugee crisis in Syria as well as the war that's destroying the country along with the internal conditions for people who live inside it. I found this book to be the most challenging to write as the material is so heavy, so full of despair and grief. Turning this real-world situation into a narrative that is compelling and passionate was a real challenge now. I found my own thoughts getting dragged down, particularly as the Syrian Civil War is still ongoing in the real world.

"Every day there's something new happening that I'd have to think about in the process of writing. It's a story that obviously can't be fully told in any single book. The question is, 'How I can tell the right story and tell it in the right way?'"

"Incorporating real-world events and contemporary human rights issues into a novel can be tricky to pull off. But that it helps that I have a background in international law and that's usually what my mysteries revolve around. I'm always doing a certain amount of research at all times whether it's relevant to a particular book or not.

"I'm constantly looking at what's happening in the world and constantly reading to better understand these issues. There are certain global events that I feel personally connected or drawn to and want to write about."

"Writing a mystery novel takes a lot of work. You want to keep the pacing intense so that people are drawn from one chapter to the next. You want readers to feel like they have to know what's coming next. In order to do all of those things, I usually outline very thoroughly so I have a sense of who all who all the players are, what their role is and what I should conceal and reveal at given times.

"Then I'll work through a first draft and identify any pacing problems and fix those elements that aren't exciting or feel like they drag down the story. I do often find it hard to keep track of clues and suspects — I'm always I writing and revising timelines and making sure that everything adds up at the end."