AMERICAN writer Justin Jordan knew he had a fertile idea for his fictional tale. He would delve into Mexican drug cartels. But which artist could render this story into riveting life?

He needed an illustrator who has a textured, firsthand understanding of Mexico, if not also its cartel violence.

The result: BOOM! Studios will unveil this summer’s Comic-Con a four-issue mini-series titled “Sombra” (Spanish for shadow). The series will debut July 20.

And its gifted artist? Mexico’s Raúl Treviño.

“I am an American — I am writing about this from a distance … ,” Jordan tells The Post’s Comic Riffs. “I feel an obligation to get it right, and no matter what — no matter how much research I do — there’s always going to be a distance between my experiences and the reality of what’s happening.

“The only way to make that work is … with someone who’s lived with it.”

Treviño and Jordan connected about the project in 2012. Treviño had long wanted to work with Jordan, but he admitted to being reluctant to take on a project like “Sombra” — for personal reasons.

Treviño has lived through cartel violence not only via newspapers and television. He also has felt its horrors more personally.

As a Mexican citizen “who has experienced misfortunes with two close family members caused by the cartels and the violence, I rejected illustrating all sorts of violent stories,” Treviño tells Comic Riffs. “However, Eric Harburn, my editor at BOOM! Studios, gave me more details about [‘Sombra’] and the motivation behind it. It was then when ‘Sombra’ got my full attention.”

Treviño began to think that through creating this artwork, perhaps he could work through some of his owns wounds caused by cartel violence against family and friends.

“I realized: Since we cannot change reality, I can face my fears and the way I see reality,” Treviño says. “It’s great to be able to mix the pleasure of creating something with my art and expressing my feelings in collaboration with Justin’s story.”

In “Sombra,” rogue DEA agent Conrad Marlowe goes missing after working in Mexico. He resurfaces, though, sparking an even more violent vigilante war against the cartels. The DEA even tasks an agent to bring in Marlowe: his own daughter, Danielle.

“I think the big problem for Danielle is the gap between what she thinks she knows and what is actually happening,” Jordan says. “She thinks she understands what happened to her father, but she’s wrong. She thinks she understands what the futile war on drugs has created, but she’s wrong there, too.”

Now, Treviño says “Sombra” has been therapeutic. “Being involved in this project,” Treviño says, “is a way of healing.”