PHOTO: SHUTTERSTOCK

A documentary depicting one of the darkest days in Pittsburgh’s history — as well as the hope and unity that emerged from tragedy — debuts tonight on HBO.

“A Tree of Life: The Pittsburgh Synagogue Shooting,” which received a private screening for community members last month at Squirrel Hill’s Manor Theater, is directed by Pittsburgh native Trish Adlesic. Her 2017 documentary “I Am Evidence,” also for HBO, won a News & Documentary Emmy Award.

Adlesic, who also produced the Oscar-nominated 2011 documentary “Gasland,” began working on “A Tree of Life” almost immediately after the Oct. 27, 2018 attack that killed 11 people. She was visiting her childhood home in North Hills at the time of the assault.

Adlesic isn’t the only Pittsburgher involved; the film credits Michael Keaton, Billy Porter and Mark Cuban among its producers. Innumerable Squirrel Hill residents, including survivors of the tragedy, are featured in the film.

While the film will include a harrowing account of Oct. 27, the film’s trailer indicates that “A Tree of Life” is no mere document of what happened that day. The film will also depict the response — one that spanned geography and, notably, religious affiliation — that supported the community in the wake of the attack.

“It’s about how we can change other people’s lives in a positive manner,” says the film’s trailer, “because that’s what the victims would’ve wanted.”

Vitally, the film will also highlight the circumstances that emboldened anti-Semitism in the United States — sadly, a subject of renewed relevance in recent weeks.

“A Tree of Life,” which also features an original song by Idina Menzel and Kate Diaz, debuts at 9 p.m. Wednesday on HBO, and will be available to stream via HBO Max.