It’s parts unknown for an unreleased documentary executive-produced by late chef and television personality Anthony Bourdain, which is now in search of a platform to make it available to fans.

The Detroit Free Press reports that Bourdain, 61, who killed himself last June, focused the four-part “passion project” on the events that shaped the Motor City — a place he admired for its authenticity and attitude. He had previously filmed there twice: once for a 2009 episode of “No Reservations” and again in 2013 for “Parts Unknown.”

While still unnamed — producers are thinking either “Once in a Great City: Detroit” or “Detroit: Once in a Great City” — the series’ first episode begins with President John F. Kennedy’s speech in downtown Detroit in 1962, when the city was a thriving car capital, the Free Press notes. Episode 4 concludes the series with Kennedy’s assassination in 1963, the Mustang’s 1964 debut and the events leading to the city’s infamous riots during the summer of 1967. One highlight is an interview with Detroit native Aretha Franklin, conducted several months before her death in August 2018.

“My determination to get a home for this project has not waned in the slightest,” Bourdain’s longtime producer Lydia Tenaglia — who has been working since January to find a home for the four-hour-long documentary — tells the Free Press. “I’m really focused on getting it out there. It’s a really beautifully executed piece of television.”

The documentary is inspired by Pulitzer-winning writer David Maraniss’ 2015 book, “Once in a Great City: A Detroit Story,” which tracks the political, racial and economic stories of the city.

Maraniss and Bourdain spoke twice about adapting the book.

“In both conversations, I was impressed by his understanding of Detroit beyond the stereotypes, his affection for the city, and his hope to present a documentary series that could accurately capture the sensibility of my book,” Maraniss, who later served as a consultant on the series, tells the Free Press in an email.

But Bourdain died as the team was putting the final touches on the film.

“The world got turned upside down, certainly in terms of projects we were doing with him and he was associated with,” Tenaglia says. “He was really the executive producer of the project and the one who was championing it and the one who was going to put his marketing muscle behind it.”

CNN, the network that aired Bourdain’s “Parts Unknown” series, had planned to air the documentary before the end of 2018, but unspecified — and ongoing — issues related to music licensing arose and more time was needed to resolve them. After awhile, the network thought a later airing wouldn’t be good timing.

Tenaglia wouldn’t specify which networks and streaming services she’s met with to pitch the Detroit project.

Either way, Maraniss, who’s seen the production several times, says he feels good about the finished product.

“I think it did justice to my book and, more important, to the city of Detroit,” he tells the Free Press. “I hope it somehow sees the light of day.”