It was one of the strangest and saddest news headlines of 1997. Inside a San Diego mansion, authorities discovered the remains of 39 members of a monastic religious sect鈥攓uickly dubbed a 鈥渟uicide cult鈥濃攌nown as Heaven鈥檚 Gate.

Lying under purple shrouds, the deceased were dressed in identical dark clothing, wearing white Nike sneakers, and with $5 bills and rolls of quarters stuffed in their pockets. Over two days, they had all committed suicide by ingesting a toxic cocktail of barbiturates and alcohol.

As details emerged about the group鈥檚 beliefs鈥攁 mashup of evangelical Christianity, New Age practices and UFOs鈥擧eaven鈥檚 Gate and its eccentric leader (known to followers as 鈥淒o鈥) became fodder for late-night TV shows.

鈥淭hey were in uniform, they were apparently into Star Trek, they were all wearing Nikes鈥攊t all seemed too bizarre to believe,鈥 says Benjamin Zeller, a  of new religious movements and author of .

But in his book, Zeller argues that Heaven鈥檚 Gate wasn鈥檛 necessarily the crazy aberration it was made out to be, nor was it a suicide cult. It was a group of 鈥渟piritual seekers鈥 who latched onto popular trends in American culture鈥攃onspiracy theories, apocalyptic beliefs, the fusion of science and religion鈥攖hat ultimately led them to a tragic end.

Marshall Herff Applewhite Meets Bonnie Lu Nettles

What Drove Heaven's Gate Followers to Mass Suicide?
Duane Braley/Star Tribune via Getty Images
Bonnie Lu Nettles (left) and Marshall Herff Applewhite (right) speak at a meeting on October 28, 1975, in the auditorium of the Native American Center in Minneapolis, Minnesota.

The origins of Heaven鈥檚 Gate stretch back to 1972 when a nurse named Bonnie Lu Nettles met a seminary dropout named Marshall Herff Applewhite. Both Nettles and Applewhite were experiencing spiritual crises, says Zeller. Nettles was going through a divorce, and Applewhite, an evangelical Christian, felt like God was calling him to a new vocation.

The two became spiritual soulmates. Nettles claimed to be in communication with spirit guides and angels and practiced astrology and yoga. Applewhite sought answers in the Bible, particularly the book of Revelation, which foretells the events that will herald the end of the world.

Together, Nettles and Applewhite received their own revelation: The Bible, when it talks about God, Jesus and angels, was actually talking about extraterrestrials, a superior race of aliens who appeared to us as gods. In the last days, the aliens will arrive in their spaceships, destroy or 鈥渞ecycle鈥 the Earth, and save the faithful who were ready to 鈥済raduate鈥 to the 鈥淣ext Level.鈥

鈥淲hat Nettles and Applewhite were offering was an E.T. version of what other Christians would call the Rapture,鈥 says Zeller, adding that the idea of mixing UFOs with religion wasn鈥檛 new; it was already popularized by the 1968 best-seller Chariots of the Gods. Specifically, Nettles and Applewhite came to believe they were the 鈥淭wo Witnesses鈥 prophesied in who would testify and teach on Earth before the Final Judgment. According to the prophecy, the Two Witnesses would be killed and then resurrected.

鈥淣ot by magic or by a miracle, but by extraterrestrial technology,鈥 says Zeller. 鈥淲hen the Bible referred to Jesus ascending to heaven in a 鈥榗loud,鈥 Nettles and Applewhite knew that the cloud was really a UFO. The UFOs were their salvation.鈥

'The Class' Attracts Students

By 1975, Nettles and Applewhite were fixtures of the alternative spirituality scene in California and Oregon. They opened a New Age store and began offering classes where they would share their message: this earthly life was an intermediate realm where we learn to battle evil (bad aliens), transcend our human bodies and transform into perfected beings.

鈥淭hey never called themselves Heaven鈥檚 Gate,鈥 says Zeller. 鈥淭he group鈥檚 name for themselves was 鈥楾he Class.鈥 Nettles and Applewhite were seen as 鈥榯eachers鈥 and their followers were 鈥榮tudents.鈥 To this day, ex-members call each other 鈥楥lassmates.鈥欌

Over time, Nettles and Applewhite received more revelations. They came to believe that they themselves were aliens who had been sent to Earth to prepare humankind for the end. Nettles and Applewhite changed their names to Ti and Do, and The Class took on a monastic feel. Members were encouraged to be celibate and to wear special clothing (modeled after Star Trek uniforms).

Even with their unusual beliefs and odd dress, Zeller takes issue with calling The Class a 鈥渃ult鈥 or saying that its members were 鈥渂rainwashed.鈥 If we choose to use those terms, he says, then the same could be said of all religions.

鈥淭hey acted like a religion,鈥 says Zeller. 鈥淭hey had beliefs and practices, rituals and prayers, they talked about the meaning of life, the end of the world, and what happened after death. They looked like a religion, but like some other religions, they had teachings which I would not promote or accept.鈥

After Nettles' Death, a New Vision of the End

In 1985, Nettles died of cancer. This shook the group鈥檚 belief system to the core, since members previously thought they would be physically transformed into perfect beings while alive. After Nettles鈥 death, a new idea emerged鈥攎embers would have to shed their imperfect human bodies, at which point their consciousness would transfer into a 鈥淣ext Level鈥 alien body.

Like Ti and Do, the members increasingly saw themselves as alien visitors temporarily inhabiting human bodies. Like other fringe groups, they developed elaborate conspiracy theories to explain why so few people had accepted their message.

鈥淭hey didn鈥檛 call it the 鈥楧eep State,鈥 but they believed that the government was allied with the media and corporate interests to hide the truth from the people,鈥 says Zeller, 鈥渢hat space aliens are real and that the government is working with bad aliens known as 鈥榯he Luciferians.鈥欌

In the early 1990s, Applewhite posted his first online writings, first to Usenet message boards and eventually on called Heaven鈥檚 Gate. The response, Zeller , was 鈥渦niformly negative,鈥 which led Applewhite and other members to slowly give up on convincing the rest of the world to prepare for the Earth鈥檚 impending 鈥渞ecycling.鈥

Hale-Bopp Comet Discovery Prompts Group to 'Graduate' from Earth

Instead, the group looked for signs of the extraterrestrials鈥 arrival, which they found in the  of the Hale-Bopp comet. Astronomers calculated that the comet, which was 1,000 times brighter than Halley鈥檚 comet, would pass closest to the earth in March of 1997. Applewhite came to believe that the Hale-Bopp comet was the perfect cover to hide a 鈥渃ompanion鈥 alien spacecraft, and when it arrived the members of Heaven鈥檚 Gate would be ready.

On March 22 and 23, 1997, the members of Heaven鈥檚 Gate took what they believed was the final and necessary step to escape the Earth鈥檚 destruction and graduate to the Kingdom of Heaven and their exalted alien bodies. In the end, 39 people, including Applewhite, killed themselves in the hopes that their consciousness would ascend to the heavens to meet the passing spaceship.

The stunned rest of the world was left with hours of video recordings by Applewhite and extensive writing on the group鈥檚 website, including a page titled 鈥.鈥 Ultimately, the group concluded that 鈥淭he true meaning of "suicide" is to turn against the Next Level when it is being offered.鈥 When the Kingdom of Heaven was offered, they took it.

鈥淢embers said they joined of their own free will,鈥 says Zeller. 鈥淭hey recorded exit statements. They wrote autobiographies that explained why they joined this movement. If we're going to call that brainwashing, then I don鈥檛 know what we鈥檙e going to call free will.鈥