(CNN) — As soon as some members of the Islamic Center of Muncie saw the man coming toward them, they knew he was trouble.

He was a big guy with broad shoulders, marching toward their mosque with his head down and his face flushed red from what looked like anger. It was Friday at Muncie Islamic Center in Muncie, Indiana, and the mosque was filling with people who had come for afternoon prayers. As an outsider with a USMC tattoo on his right forearm and a skull tattoo on his left hand, he stood out.

His name was Richard “Mac” McKinney, and he was there not to worship but to destroy. He was a former US Marine who had developed a hatred toward Islam during combat in Iraq and Afghanistan. His fury deepened when he returned home to Muncie to see how Muslims had settled into what he called his city, and even sent their children to sit next to his daughter at her elementary school.

Unable to contain his anger, he went to the Islamic center that day in 2009 on what he saw as his final mission. He was going to plant a bomb at the mosque in hopes of killing or wounding hundreds of Muslims. He was on a scouting mission to pick a location to hide his bomb and to gather intelligence that would validate his assumption that Islam was a murderous ideology.

“I told people that Islam was a cancer; and I was the surgeon to cure it,” he says.

But when McKinney entered the mosque, he encountered a form of resistance that he had not planned for. Something happened that day that would change him in a way he never expected.

The people whose lives he intended to take would end up saving his life.

McKinney and the mosque’s members built ‘an impossible bridge’ to one another

What happened to McKinney at the mosque is so dramatic that it sounds like something from a movie. And in fact, it is.

McKinney’s transformation is the subject of a riveting documentary short called “Stranger at the Gate.” The film, which won a special jury prize at the 2022 Tribeca Film Festival, recounts how McKinney abandoned his plot and ended up converting to Islam and embracing a surprising role at the mosque. “Stranger at the Gate” is up for an Oscar this Sunday in the documentary short category and counts among its producers Malala Yousafzai, the acclaimed activist and recipient of the Nobel Peace Prize.

McKinney recently spoke to CNN via video about his unlikely conversion. Wearing a blue “Say No Hate to Hate,” T-shirt over his muscular frame and a long white beard that made him look like a buffed Santa Claus, McKinney told his story in a blunt, no-frills manner that underscored his 25 years in the military.

McKinney says he thought his Friday afternoon visit might end with his death.

“By the end of the night, I figured they would have me in the basement with a sword to my throat,” he says.

Instead, several mosque members stepped forward and disarmed McKinney with some shrewd choices that may have saved their lives.

The film cites one staggering act of kindness: Mohammad S. Bahrami, a native of Afghanistan and co-founder of the center, ended up hugging McKinney and erupting in tears.

“To this day, it still doesn’t make sense to me,” McKinney says about the gesture.

Joshua Seftel, the film’s director, says he was drawn to McKinney’s story in part because of his own experiences facing antisemitism growing up in Schenectady, New York, in the late 1970s and early ’80s. Classmates lobbed antisemitic slurs while throwing pennies at him.

Seftel made his film as part of “The Secret Life of Muslims,” an online video series. He says McKinney’s story gave him hope that even some of the deepest divisions in the US can be transcended.

“They were able to build an impossible bridge to one another,” Seftel says of McKinney and members of the Muncie Islamic center. “If that could happen, anything is possible. They gave us a blueprint for how we could all do this.”

McKinney was looking for a way to forgive himself for what he did in war

To reveal too many details about how McKinney converted would rob the film of its impact. But there are some scenes and characters that beg to be described.

One was the story of how McKinney was changed by combat. McKinney’s struggles after he returned to Muncie in 2006 are a prime example of the adage, “In war there are no unwounded soldiers.”

McKinney says he was trained to see the Iraqi and Taliban soldiers he fought not as human beings but as paper targets on a shooting range. He also says he struggled to find a new community after he left what he calls the “band of brothers” he fought alongside during his service. Once he returned home, he drifted into drinking and womanizing to numb his wartime experiences.

Seeing Muslims only caused his pain to resurface. He resented the presence of Muslims in Muncie because it seemed to make a mockery of the sacrifice he and his comrades made in Iraq and Afghanistan.

“I wasn’t willing to share,” he says. “I saw America as mine. I bled for this. It was a ‘You don’t belong here’ kind of thing.”

Layered in his grief was also guilt over the lives he had taken during combat. He wasn’t just at war with Muslims; he was at war with himself.

“He can’t completely forgive himself for what he did,” says Dana, one of his ex-wives, in the film.

Then he met the ‘Mother Teresa’ of Muncie’s Muslim community

There were plenty of people who helped diffuse McKinney’s anger and guilt.

One was Jomo Williams, an African American member at the Islamic center who knew something about anger. His great-great-grandfather was lynched and castrated by a White mob. He carried a hostility toward White people until he converted to Islam.

Williams was one of the first to spot McKinney striding toward the mosque, looking agitated and angry.

“When I saw him, he was walking kind of fast, his head was kind of down, and he was kind of red in the face a little bit,” Williams says in the film. “I knew something was wrong.”

As viewers can see in the film, Williams later asked McKinney a question that set him on his path to conversion.

But if there is a heroine in “Stranger at the Gate,” it’s a magnetic woman everyone calls “Sister Bibi.”

Bibi Bahrami is a co-founder of the Islamic Center of Muncie and played a pivotal role in McKinney’s conversion. Bahrami and her husband, Mohammad, are pillars in the Muncie community. They have six children, several who have gone on to graduate from Ivy League schools and pursue assorted careers. She is a whirlwind, volunteering at a local women’s shelter, the YWCA, Muncie Rotary Club and the Interfaith Fellowship while serving on local boards and hosting fundraisers for local politicians.

She embodies the Quranic verse on the Islamic center’s website: “The reward for goodness is nothing but goodness.”

She, too, knew the damage done by war. Her family in Afghanistan was displaced when the Soviet Union invaded in 1979. She fled her country in tears and lived six years in a refugee camp in Pakistan before marrying and making her way to the US.

Seftel calls her the “Mother Teresa of the Muslim community” in Muncie. She’s someone who takes in strangers in need in the community to clean and iron their clothes and feed them meals. Her reputation is such that refugees from other countries somehow find her number and address to track her down for help.

She says she experienced an awakening when she came to the US and became a citizen.

“The freedom of choice is the biggest thing for me,” she says about what she likes about the US. “I’m still able to practice my religion, to continue covering (wearing her hijab) and get an education. I was inspired by these opportunities. I truly love this country.”

Her service is also part of her worldview. Showing kindness to a stranger is central to the Muslim faith.

“God created all of us to get to know each other and take care of each other — not to despise,” she says.

She reached out to McKinney with a bold invitation

Bahrami’s hospitality is remarkable considering many Muslim Americans are still treated like strangers in their own country. Hate crimes against Muslims in the US surged 500% from 2000 to 2009, according to a Brown University study, reflecting an increase in anti-Muslim sentiment after the 9/11 attacks.

Many still face hostility, surveillance and questions over their patriotism.

Some members of the Muncie Islamic center stopped attending the mosque because they were afraid of the burly Marine with the tattoos.

But Bahrami extended her circle of compassion to include McKinney. She invited him to her home and prepared a hearty Afghan dinner of chicken, rice, an eggplant dish and a green yogurt dip seasoned with cilantro and lime juice.

McKinney devoured the meal.

“He tried everything,” she says, chuckling. “He was not picky.”

The meal became another bridge to McKinney. He kept visiting Bahrami and others at the center. He read the Quran, Islam’s holy book. He formed friendships. He told mosque members about his time in combat and they accepted him.

Eight months after McKinney’s initial visit to the mosque, he converted to Islam. After the ceremony he was greeted with what he called “a mosh pit of hugs” from the people he once intended to harm. Eventually he even served two years as president of the Islamic Center in Muncie.

When asked how he felt when he was showered with hugs following his conversion ceremony, McKinney broke into a wide, boyish grin:

“I was good with that.”

McKinney now has a new mission

Ask him why he converted, and he becomes more talkative. He says the more time he spent with mosque members, the more he discovered how much he had in common with them. He once thought of becoming a preacher when he was a boy, and he discovered that Islam shares some similarities with Christianity.

Islam, Christianity and Judaism, for example, are connected in many ways. Each is a monotheistic religion that traces its origins back to Abraham. Many Muslims, for example, consider Jesus a great prophet born to a virgin mother.

But it was the kindness of the people at the center, and the community they shared with him, that proved most decisive in his conversion, he says.

“They were just happy. They were just plain pleasant,” he says. “And I really needed that in my life.”

He says that if the people at the center had reacted with hostility that first day, the result probably would have been bloodshed.

Would it be fair to say their kindness saved his life?

“No, no,” he says. “It’s too little to say.”

McKinney says he probably would have attacked the mosque and eventually received the death penalty if not for how he was treated.

Today, McKinney is trying to return the kindness that was extended to him. He earned a bachelor’s degree in social work with a minor in peace and conflict resolution and now travels the country to speak about his experiences.

Has he been able to forgive himself now that he’s converted? He pauses before answering.

“It’s a work in progress,” he says in his gravelly baritone. “How about that?”

Yet as a beautiful scene in the film illustrates, others have forgiven him.

It shows McKinney standing beside Williams, the African American man who lost his great-great-grandfather to hate, silently raising their palms together in prayer as a ribbon of golden sunlight streams into the mosque.

That image conveys more than words could say. McKinney is no longer the stranger at the gate.

He’s found a new band of brothers and sisters — not in the heat of battle, but in faith.

A Marine was plotting to bomb an Indiana mosque. Then his plans took a surprising turn