( CNN ) -- A self-help guru who was convicted in the deaths of three participants in an Arizona sweat lodge ceremony deserves a new trial , his attorneys argued Tuesday . James Arthur Ray was found guilty of negligent homicide in the deaths of the participants , but an Arizona jury in June deemed him not guilty of manslaughter charges . Negligent homicide means a defendant should have known better , while manslaughter suggests that the defendant knew and blatantly disregarded this knowledge . Ray 's attorneys went before a Superior Court judge in Yavapai County , Arizona , claiming he should be tried again because of prosecutorial misconduct , a court official said . The official , who was not authorized to speak to the media , said the hearing started shortly after 11 a.m. MT and ran until a lunch break . The hearing is scheduled to run for the rest of the day . The defense claims the prosecution did not disclose evidence on time . Ray 's sentencing , originally scheduled for July 25 , has been pushed back . The case stems from an October 2009 ceremony in Sedona , Arizona . Prosecutors claimed that Ray 's recklessness in operating the sweat lodge 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. More than 40 others were uninjured . Prosecutors argued that 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 . They also said Ray did n't monitor the temperature inside the lodge or the well-being of participants and was indifferent to those clearly having trouble . Ray 's lawyers countered that what happened was 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 did n'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 . Event participants paid up to $ 10,000 to seek `` new areas of consciousness '' at the October 2009 Spiritual Warrior retreat in the desert , according to trial testimony . Many had attended previous James Ray International seminars .
Defendant 's lawyers want a new trial . They say the prosecution did not disclose evidence on time . Ray has been found guilty of negligent homicide . The case stems from an October 2009 ceremony in Sedona .