PHOENIX- A self-help guru who organized an Arizona sweat lodge ceremony last year in which three people died was arrested on manslaughter charges Friday, authorities said.

James Ray, renowned for his best-selling books on spirituality, was arrested at a law office in Prescott, Arizona close to the Sedona retreat where the fatal October ceremony was held, said Yavapai County Sheriff Steve Waugh.

He was indicted by a grand jury on manslaughter charges after a prolonged investigation during which police held hundreds of interviews.

The victims have been named as Kirby Brown, 38, of Westtown, New York; Liz Neuman, 49, of Prior Lake, Minnesota; and James Shore, 40, of Milwaukee, Wisconsin.

Another 19 people were also hospitalized after participating in a "purification" ceremony at the Angel Valley Retreat Center and fasting for 36 hours.

The ceremony held by Ray, president of the multi-million-dollar James Ray International company in California, took place in a luxury sweat lodge.

Participants were told they could sweat out their worries in the enclosure, where hot rocks were placed inside a tent.

About 60 people participated, with a price tag of around 9,000 dollars each.

Emotions ran high as the drama unfolded in and around Sedona, known for its many retreats.

Ray has repeatedly denied he did anything wrong.

"The charges are unjust and we will prove it in court. This was a terrible accident - but it was an accident, not a criminal act," his attorney Luis Li said in a statement.

"James Ray cooperated at every step of the way, providing information and witnesses to the authorities showing that no one could have foreseen this accident. We will now present this evidence in a court of law, and we are confident that Mr Ray will be exonerated."

Melinda Martin, who once worked for the motivational speaker and was present during the ceremony, later told CNN that her former boss was "completely oblivious to the pandemonium that was taking place in the lodge."

Another participant, who gave her name as Beverly, told the television network "there was no way he was helping anybody."

In a letter addressed to the Yavapai Country Attorney's Office in early January, Li said that Ray and his team "relied on Angel Valley to provide a safe environment, warned people of the risks, did not force people to participate, did not prevent them from leaving and did everything they could to prepare for any problems and to assist when problems arose."