In 2013, Toronto epidemiologist Dan Werb travelled to Tijuana to investigate the spread of HIV in the Mexican border city. What he found was an ongoing epidemic of missing and murdered women. In searching for the roots of the violence, Werb found himself in factory slums, drug dens and corrupt police corridors on a trail that led north over the border.

Werb documents his research in his first book City of Omens, which is a finalist for the 2019 Governor General's Literary Award for nonfiction. He is an assistant professor at the University of California San Diego and University of Toronto.

The winners of the Governor General's Literary Awards will be announced on Oct. 29, 2019.

Werb spoke to CBC's On The Coast in June 2019 about his book.

"I started work in Tijuana in 2013. Ostensibly, I was there to study an HIV epidemic among the city's population of people who injected drugs, some of whom were women who worked in the sex trade. Lots of them were living in a canal and injecting drugs in spaces called picaderos, which were crumbling buildings and hidden spaces among the city.

"What I discovered was that HIV was disproportionately impacting women, but it wasn't the only epidemic that was impacting women there. There were actually a whole host of reasons why women were so vulnerable to dying in Tijuana. What struck me were that all these different reasons — HIV, overdose, death at the hands of cartels, police enforcement — all of these were aspects of a larger epidemic, which I termed as a femicide."

"Tijuana was established in the late 19th-century and it was really established to feed Americans vices. It's a border city. It's right across the border from San Diego and it made its reputation as a gambling hub, as a place to buy alcohol during prohibition and, more recently, as a place to buy sex in its quasi-legal red light district.

"But, as the border has hardened over the past 15 or so years and it's become more and more difficult for Americans to travel abroad and for people to enter the United States, the clientele of that red light district has dwindled. That has done more to damage the women there and place them in a vulnerable position."

"One story that stands out is the story of Rosa, who is now in her 50s and is a sex worker who has been working in Tijuana for 30 years. She described to me an image that has haunted me. She described being victimized at the hands of both drug cartels and police officers. When I asked her what the differences were between the two, she simply said that the police wore hoods to hide their identities while the cartels were so brazen that they didn't have to. That sums up Tijuana and the vulnerabilities that women face there, I think, pretty succinctly."