( CNN ) -- An investigation into the deaths of two people who spent up to two hours inside a `` sweat lodge '' at an Arizona retreat last week has been elevated from an accidental death investigation to a homicide inquiry , Yavapai County Sheriff Steve Waugh told reporters Thursday . Self-help author James Arthur Ray has hired investigators to investigate two deaths at an Arizona sweat lodge . Authorities said James Shore , 40 , of Milwaukee , Wisconsin , and Kirby Brown , 38 , of Westtown , New York , died Friday at the Angel Valley Resort after spending up to two hours in the sauna-like sweat lodge . Nineteen others were treated for injuries . One person remained hospitalized Thursday in critical condition , Waugh said . The dead and injured were attending a program by self-help author James Arthur Ray , authorities said . A search warrant was executed Wednesday at the James Ray International offices in Carlsbad , California , the sheriff said . Authorities were attempting to determine whether documents exist on how to construct sweat lodges and on their proper use , as well as documents showing whether participants were advised of the risks of sweat lodges either before or during the program . They also were searching for rosters from past events , Waugh said . Police would not say what , if anything , was found in executing the search warrant . Watch what goes on inside the 'sweat lodge ' » . Asked why the deaths have been classified as homicides and the investigation upgraded , Waugh said , `` We believe there are indications that it was not accidental , and ... we feel that there should be some culpability on some individuals . '' Those individuals could include Ray and possibly others , he said . A spokesman for Ray said authorities should be focusing on the investigation rather than talking to reporters . `` The Sheriff 's Department is trying this case in the media , '' said Howard Bragman , noting that Thursday 's news conference was the sheriff 's second this week . `` There were no additional facts presented today ; there were implications . I find words like 'homicide ' -- when they do n't have all the facts -- inflammatory and inappropriate at this time , and I think they 're purposely inflammatory . ... Let 's show as much zeal with the investigation and getting to the facts as they have in trying to tar my client , '' Bragman said . The sweat lodge was meant to be a `` spiritual awakening '' exercise for the participants in the `` Spiritual Warrior '' program , Waugh said . A sweat lodge is a dome-like structure covered with tarps and blankets . Hot rocks and water are used to create steam in the enclosed environment . The owners of the resort built the sweat lodge , Waugh said , under Ray 's direction . A nurse on Ray 's staff was present during the event , police have said . At least one of those who died was in the back of the structure , Waugh said . Ray was positioned near its door . There were no seats , he said ; participants either sat or lay on the floor . On Tuesday , Ray said he has hired his own investigators to determine what happened at his Arizona retreat , located in a secluded valley 20 minutes from Sedona . `` I have no idea what happened . We 'll figure it out , '' Ray said . `` I 've lost people I love and really care about . '' Ray is the author of the best-selling book `` Harmonic Wealth : The Secret of Attracting the Life You Want . '' Ray , described on his Web site as a `` personal success strategist , '' has appeared on CNN 's `` Larry King Live '' and the `` Oprah Winfrey Show , '' and is featured in the self-empowerment film `` The Secret . '' The use of sweat lodges for spiritual and physical cleansing is a part of several Native American tribes ' cultures . A traditional Native American sweat lodge is a small dome-like structure made of willow branches carefully tied together and covered in canvas . Rocks are heated in a nearby fire pit and placed inside the lodge , and water is poured over them to create steam .
2 died , 19 die in sweat lodge at Penn State . Self - help author James Arthur Ray sponsored the program . ` ` We believe there are signs that it was not accidental , '' they say . Ray says he 's hired private investigators to determine what happened .