Park City • Rock star Dan Reynolds was once a Mormon missionary, and in a documentary that premiered at the 2018 Sundance Film Festival, he declares a new mission: to urge leaders of his faith to stop shaming their LGBT members.

“A determined Mormon is a scary thing, I can tell you that, because they don’t stop,” Reynolds, singer for the band Imagine Dragons, declares in “Believer,” a documentary that received a standing ovation from some 500 Sundance attendees at its first screening late Saturday night.

The movie will receive a broader audience this summer, director Don Argott told the audience after the film. “Believer” was picked up before the festival by HBO Documentary Films, with plans for a theatrical release this summer and a debut on HBO after that.

(Don Argott | courtesy Sundance Institute) Dan Reynolds, frontman for the band Imagine Dragons, is profiled in Don Argott's "Believer," which will screen in the Documentary Premieres section of the 2018 Sundance Film Festival.

There’s another audience Reynolds hopes will watch the movie: the leadership of The Church of Jesus Christ of Latter-day Saints.

“I hope that [LDS Church President Russell M. Nelson] and the apostles take the time to watch this documentary, to see the faces, to hear the voices, to hear the stories, of these Mormon youth,” Reynolds told The Tribune earlier Saturday. Reynolds added that he would like to talk about “how to have real change. Because speaking in platitudes of love will not create that change.”

Reynolds said he “is trying to stay really optimistic right now” about last week’s selection of Nelson as president of the LDS Church and Dallin H. Oaks and Henry B. Eyring as his counselors. The film includes harsh rhetoric about LGBT people, including LDS General Conference talks by Nelson in 1995 and Oaks from last October. (The movie was completed before the death of President Thomas S. Monson on Jan. 2 and will likely be updated before general release.)

Reynolds’ friend Tyler Glenn, lead singer of the band Neon Trees, is less hopeful.

“It’s a setback,” Glenn told The Tribune on Saturday. “I want everyone to feel safe, and that’s a very unsafe choice.”

Glenn, who grew up Mormon but is now inactive, came out as gay in 2014. He appears prominently in the movie, as Neon Trees played before Imagine Dragons at the LoveLoud Festival.

Reynolds told the Sundance audience that he spoke to a couple of LDS apostles after he staged the LoveLoud Festival, a benefit concert in Orem last August designed to bring together Mormons and the LGBT community. Much of “Believer” focuses on the organization of the festival, the first of what he vows will be an annual event.

“They said, ‘You know what? We do have a problem with our youth,’” Reynolds said of his meeting. He said his reply was “if you’re telling them their innate sense of love, which is unchangeable, is wrong, you’re going to have this problem.”

Reynolds told The Tribune that he hopes to continue a dialogue with LDS leaders, “to move forward and progress towards an actual healthy place for our LGBT youth. Because where it stands right now, it’s not.”

The film, directed by Argott and produced by Live Nation Productions, outlines policies over what the LDS Church calls “same-sex attraction,” including encouraging LGBT people to marry members of the opposite sex (a stance the faith has since officially abandoned) or to abstain from sex altogether.

Advocates point to the November 2015 edict — labeling same-sex Mormon couples “apostates” and forbidding their children from baptism and other religious rites until they become adults — as particularly divisive and harmful.

“As long as those policies are still intact,” Reynolds said, “our LGBT youth still have high percentages of depression, anxiety and suicide.”

Last week, Gov. Gary Herbert formed a state task force to examine the rising number of Utah teens taking their own lives. One possible cause often cited is the fear of being ostracized because of their sexual orientation.

There’s another audience Reynolds said he would like to reach with “Believer”: students at LDS Church-owned Brigham Young University. He told the Sundance audience that he was set to attend the school until he was expelled after admitting to having sex with his girlfriend, violating the school’s Honor Code.

During Saturday night’s Q&A, he joked, “I’m still technically a student at BYU. … I would like to show my student film.”