First came the pungent smell of death. When Rio DiAngelo pushed the door open into the eerie silence, he knew beyond doubt what he would find.
Dousing his shirt with cologne and pulling it over his nose, he stepped into a scene of horror that would both shock and bewilder the world.
Inside the mansion in San Diego, California, 39 of his friends lay dead in their beds after the largest mass suicide on US soil.
All members of a bizarre cult, they had each drunk a lethal cocktail of drugs mixed with vodka in a deluded attempt to leave earth and board an alien spaceship.
The tragedy, ten years ago this week, was timed to rendezvous with a UFO they believed was trailing the Hale-Bop comet blazing in the sky above them.
Today the sect's only survivor talks for the first time about the astonishing and ultimately deadly world of the Heaven's Gate cult. And of the day he had raced to their headquarters, fearing the worst.
Rio had been in on their macabre plan until just four weeks before their deaths, had helped find the poison recipe and had been measured up for the uniform each would wear to 'exit' their bodies.
And as he went from room to room, seeing the lifeless bodies of people he had spent every waking hour with for the past three years, he realised just how close he had come to joining them.
He remembers: "I entered through the kitchen.
Everything was spotless, like always. But there was nothing going on, everything was quiet. Then I turned the corner and saw the first body, covered in a purple shroud on a mattress on the table. It was one of my best friends.
"I went upstairs, yelling for people in case anybody was still alive, but no one answered. There was a body in every room I went into."
All were dressed in a tracksuit with a 'Heaven's Gate Away Team' patch on the sleeve, as well as black Nike running shoes with the comet-like slash on the side. The 21 women and 18 men had each packed a suitcase for their journey and each had five dollars in their pockets.
He says: "I forced myself to go into each room and check everyone. With each body I came across the loss I felt became too much to bear. They were my closest friends who I loved dearly."
Rio's first contact with the group had been in January 1994, when he attended one of their meetings in a Californian hotel.
He had listened as nine cult members, in identical loose clothes and short haircuts, described how an alien spacecraft would arrive to take the chosen few away to paradise.
Their 65-year-old leader Marshall Applewhite had started the cult in 1972 with Bonnie Nettles, who he had met while undergoing treatment in a mental hospital.
They abandoned their human names, instead calling themselves Guinea and Pig, then Bo and Peep, before finally settling on Do and Ti.
Ti died of cancer in 1985 but Do, claiming he was Jesus returned to Earth, said he continued to communicate with her.
Despite their fantastic beliefs, Rio was completely taken in. "I'd just turned 40 and recently got divorced. I was trying to find meaning in life.
"The first thing I noticed when I attended the Heaven's Gate meeting was how calm, happy and self-controlled they seemed. It was like they had found what I'd been searching for all my life."
Rio decided to join the group, and on his first day had his hair cut short and was given the new name 'Neo'.
For the next three years he lived with the wandering commune of believers as Do, their Messiah, instructed them in alien ways.
Many of their rituals seem absurd now. On some days members had to report to their superiors every 12 minutes, while on other days they were required to wear a cone on their heads - as they would in their alien bodies.
They were forbidden from having sex and were not allowed to hug each other or even shake hands. Some members - including their leader Do - actually castrated themselves in order to better control their bodies.
Many common words were also changed, so that members would not remember their human past when they were eventually carried off into space. House became "craft" and the kitchen became "nutri-lab", for instance.
And for more than two years Rio lived in this eccentric community, sharing their strange but essentially harmless lives. But then their Messiah's message took a sinister turn.
Rio remembers: "In December 1995 Do sat us all down and said, 'It really looks to me like there may be another way to do this… we may have to leave our bodies behind. One guy walked out, but the rest of us didn't have a problem with it. We didn't think we belonged to our bodies anyway, and we trusted Do implicitly.
"We found a suicide recipe that used Phenobarbital, vodka and apple sauce. Do and some of his helpers went to Mexico and bought enough of the drug for the entire group."
Eleven months later, an amateur photographer took a photo of the Hale-Bop comet which showed a mysterious object trailing in its wake.
The photo was later exposed as a hoax, but Do convinced the group, now living near San Diego in California, that it was a spaceship coming to take them away - and that his deceased partner Ti was flying it.
Just a month before the suicides, Rio decided he wanted to leave the commune, moved to Beverly Hills and started working for a web design company.
He says: "Do agreed that this was part of the plan that I stay behind. We used to speak by phone or email all the time.
More about Heaven's Gate"After I'd gone, they all went to Las Vegas and Seaworld. They had some surplus money and wanted to use it all before they left."
Then on March 27, 1997, a parcel arrived for him at his office.
"Even before I'd opened it I knew it had happened. I waited until I was home to open the parcel, which contained a video tape and a message. I didn't have a video player at home, so I just opened the note, which read: "By the time you read this, we will have exited our bodies."
The next morning Rio, filled with dread, drove to the San Diego mansion where he discovered the awful truth and called the police.
The cult members, aged between 26 and 72, are believed to have died in three groups, 15 the first day, 15 the next and nine on the third. In the heat of the Californian spring, many of the bodies had already started to decompose.
Ten years on, he is still haunted by the events of that day, but relieved that he didn't join his friends in the mass suicide which shocked the world.
He says: "Over the last decade I've been on an emotional rollercoaster. I still miss my friends so much and I still haven't met anyone who can compare to them.
"Not a day goes by that I don't think about them.
"I'm the last Heaven's Gate member on Earth, so there must be a reason why I'm still here. But although I still want to live like them, dying like them definitely isn't part of my plan."