It was only after his father’s death that Monterrey film director Gian Cassini, 34, learned what his father did for a living: he was a drug cartel sicario. The man had often been absent in Cassini’s youth, and now he knew why.

His father was killed during the violent drug-trafficking crackdown by the Felipe Calderón administration, Cassini said.

“At the time I remember it was like … I wanted to keep it in a box, as if it were separate from him. I thought, ‘I don’t need this in my life,’” Cassini said.

But talking with his father’s family and seeing their loss, Cassini became more interested in the dichotomy between the man his family knew and the violent business in which he had been involved and decided to make a documentary about his family’s experience. Now, after nine years of work, the film Comala is debuting at the Toronto International Film Festival.

“Initially, I thought I’d make a fictional film, but when I met with my family and saw everything, how the absence of a son, a brother and a father affected them, I was inspired [to make a documentary] … Little by little I convinced them to participate, which is admirable because we all have things we are ashamed of or things we don’t want to confront … in the end, they threw themselves in and were completely honest with me,” Cassini said.

Rather than focusing on sensationalist violence, the film looks at the toll his father’s line of work took on his immediate family. One of the film’s goals, Cassini said, was to spread awareness of the problem of violence, which is often normalized.

“It’s terrifying how we have arrived at the point of normalizing the violence of narco-trafficking. It is something that seems to no longer affect us, and is even celebrated [in popular culture] … It’s worth remembering that … in the midst of all of that, we are still human beings and what is happening affects us,” Cassini said.

The Toronto festival runs from September 9 through 18.

With reports from Reforma