Read more about this story from CNN affiliate KTVK.
(CNN) -- A judge sentenced a self-help expert to a total of two years in prison Friday for his role in the deaths of three people in a 2009 sweat lodge ceremony in the Arizona desert.
Prosecutors had sought consecutive three-year sentences for James Arthur Ray on each of the three counts of negligent homicide on which a jury convicted him. The judge instead imposed three two-year terms, to be served concurrently.
Ray and his attorneys asked for probation, but Judge Warren R. Darrow said the evidence shows "extreme negligence on the part of Mr. Ray."
"A prison sentence is just mandated in this case," he said.
During the trial, prosecutors argued that Ray's recklessness caused the deaths of Kirby Brown, 38, of Westtown, New York; James Shore, 40, of Milwaukee; and Lizbeth Marie Neuman, 49, of Prior Lake, Minnesota. At least 15 others who took part in the sweat lodge ceremony became ill.
The lodge, made of willow trees and branches and covered with tarpaulins and blankets, was heated to a perilously high temperature, causing the participants to suffer dehydration and heatstroke, prosecutors alleged.
They also said Ray didn't monitor the temperature inside the lodge or the well-being of participants and was indifferent to those having trouble.
Ray's lawyers countered that the deaths were the result of a tragic accident, not a crime. They asked witnesses who were in the sweat lodge whether they signed a release form warning them of the dangers. All replied that they signed, but some said they didn't read the form.
Ray's attorneys also suggested that exposure to an unknown toxin in the lodge -- perhaps a pesticide, rat poison or something in the type of wood used to heat the rocks -- could have caused the deaths.
Ray tearfully told the court that he has "no excuse" for what happened that October day or since.
"At the end of the day, I lost three friends, and I lost them on my watch," he said. "And whatever errors in judgment or mistakes I made, I'm going to have to live with those for the rest of my life."
Ray asked Darrow to sentence him to probation, saying he is no threat to society and promising never to conduct another sweat lodge ceremony again.
"It pains me beyond belief to be here today, with the best of intentions gone wrong," he said.
Before Darrow announced his judgment, prosecutor Sheila Polk characterized Ray as a dangerous "pretender" who had cast himself as a victim of an overzealous prosecution.
And relatives of the victims told Darrow that Ray has done little to redeem himself and that he deserved the maximum possible sentence of nine years in prison.
"My heart's been ripped out. My life has been blown apart, and the pieces are yet to land," said Virginia Brown, Kirby Brown's mother.