Kyle Josef Nolan and his parents knew exactly why the 18-year-old Sebastopol man traveled to a retreat center in the Peruvian jungle: to participate in an "ayahuasca ritual," ingesting a psychoactive concoction used by Amazonian people for centuries and popular with westerners, including the musician Sting.

But the 10-day program at the Shimbre Shamanic Center went tragically wrong, and the operator, a shaman named Jose Manuel Pineda Vargas, attempted to cover up Nolan's death and lied to his mother when she first arrived in Peru, according to Sean Nolan of Petaluma, Kyle's father.

Peruvian National Police said they arrested Pineda, 58, who called himself "Master Mancoluto," and two men who allegedly helped bury Nolan's body on the shamanic center's property outside the city of Puerto Maldonado in southeastern Peru near the Bolivian border.

A YouTube video depicts Pineda leading authorities to the spot where Nolan's body was unearthed.

Ingeborg Oswald of Sebastopol, Nolan's mother, and his sister, Marion Nolan, were in Peru Friday waiting to bring Nolan's body home and also obtain official reports on his death, Sean Nolan said.

"This is what he wanted to do," Sean Nolan said. "This was not to be a vacation for him, but rather an experience to further open his mind."

Nolan, a 2011 graduate from Analy High School, had taken a year off from school and worked odd jobs to save money for the trip to Peru and the shamanic retreat, where ayahuasca is the "centerpiece" of a 10-day program, Sean Nolan said.

"It does have inherent risks," he said.

Sean Nolan said he was concerned about his son's use of ayahuasca, a psychoactive brew widely used by indigenous Amazonian people that contains dimethyltryptamine (DMT), a psychedelic substance that is illegal in the United States.

Nolan said he had researched ayahuasca and found no reports of "bad experiences" with it. He disputed a media report that his son had taken an excessive dose in an Aug. 22 ritual at the shamanic center.

On the program's seventh day, the shaman made a specific "preparation" for each of the participants, who had fasted and taken other steps prior to the ritual.

"Kyle drank what he was given," his father said, then found his way to a tent on a wooden platform on the center grounds. No one checked on him, and he was found dead the following day, Aug. 23, his father said.

After Kyle Nolan failed to return home on Aug. 26, his mother and sister made the first of two trips to Peru to find him. Sean Nolan said that Pineda "looked them right in the eye" and told them Kyle had seemed "despondent" and "just walked off with his suitcase."

Pineda's account apparently did not hold up under police questioning, Sean Nolan said.

Roberto Velez, the owner of the Shimbre Center, told Oswald what had really happened, prompting her second trip to Peru, Nolan said. Oswald is a veterinarian who runs a clinic in Rohnert Park.

On Friday, the Shimbre Shamanic Center's website had only two photographs: a man identified as "Master Mancoluto" and a round, unoccupied building. All other information on the site had been deleted.

More than 30 YouTube videos depict people describing their "ayahuasca experience," including Sting, who said he drank it at a big church in the jungle outside Rio de Janeiro about 20 years ago. In four minutes, Sting said, he experienced a sensation of being "wired to the entire cosmos."

"It is communion, this direct access to the Godhead or whatever you think that is," Sting said, calling it "the only genuine religious experience I've ever had."

Charles Grob, a professor of psychiatry at UCLA School of Medicine who has studied ayahuasca, said in a YouTube video that it can cause "a very painful ordeal, it can be an eternity in a hell realm, as it were."

Grob said the substance can be harmful when used along with certain anti-depressants, but he had heard of only one ayahuasca-related death. That involved an elderly Native Canadian woman whose body was overloaded with nicotine.

Kyle and Marion Nolan and their brother, Kevin Nolan, were triplets, born on Sept. 23, 1993. Kevin and Marion are sophomores at UC Santa Cruz and UC Davis, respectively.

Cesar Inda of Sebastopol said he knew the brothers at Analy High, describing them as a "dynamic duo" who looked a lot alike and were "almost inseparable."

Inda, 19, said he had seen Kyle Nolan at Santa Rosa Junior College early last month and was shocked to learn on Facebook of his death .

"It really made me think how short life can be," he said.

Sam Watkins, 19, of Sebastopol said he and Nolan were good friends at Twin Hills Middle School years ago. They played video games and listened to classic rock, including "Knocking on Heaven's Door" by both Bob Dylan and Guns N' Roses.

Watkins recalled that Nolan would come to his birthday party in the middle of summer when "everybody else was gone."