CLEARWATER, Florida (CNN) -- The Church of Scientology was charged by Florida prosecutors Friday in the death of a member. The State Attorney's office in Pinellas County filed the felony charges after a lengthy investigation into the 1995 death of Lisa McPherson. McPherson had been a member of the church for 18 years and, according to relatives, had been talking about leaving the church. McPherson, 36, died December 5, 1995, after being confined for 18 days to a Scientology property called the Fort Harrison Hotel, investigators said. Prosecutor Bernie McCabe charged the church with abuse or neglect of a disabled adult and unauthorized practice of medicine, both felonies. No injuries, but no clothes On November 18, 1995, McPherson was involved in a minor traffic accident in which police said she was not injured but removed all her clothes and told paramedics she needed help. She was admitted to a hospital after medics expressed concern for her mental health. Shortly after her arrival, members of the Church of Scientology came to the hospital, investigators said. According to court papers filed Friday, McPherson "was allowed to check out against medical advice and leave with other members of the Church of Scientology who had promised to care for her." Eighteen days later, McPherson died. An autopsy conducted by the Pinellas County Medical Examiner's office found McPherson died of a blood clot. It also found she was severely dehydrated. Medical Examiner Joan Wood concluded, according to court papers, that McPherson's "dehydration was so severe that she would have been symptomatic for days and virtually unresponsive for more than 24 hours before her death." She also indicated "the dehydration was so severe and life-threatening that in itself it constituted great bodily harm." Questionable treatment McPherson went without fluids for at least five days and possibly her entire stay at the hotel, Wood said. McPherson, who investigators said weighed about 150 pounds at the time of the traffic accident, weighed 108 pounds when she died. Attorneys for the Church of Scientology have consistently denied any responsibility for McPherson's death. Surviving family members have filed a civil lawsuit against the church. Not enough, says family Lisa McPherson's aunt, Dell Liebreich, told CNN she was relieved charges had been filed against the church but wished more serious charges had been leveled, such as manslaughter. "I feel like they killed Lisa," she said. Liebreich added that if her niece had received medical attention earlier, "it could have saved her life." Jeffrey Weiner, former head of the Criminal Defense Attorneys Association, said if the church was found guilty, no one involved was likely to be jailed because the charges had not been made against individuals. According to an FBI agent's statement filed with the felony charges, interviews with two Scientology members conducted in May 1996 described McPherson as a "guest at the hotel who was there to 'rest.'" The investigator describes various Scientology members giving McPherson medications prescribed by a doctor who had not seen her, including Valium and another sedative. The agent says McPherson was described at various times as delirious and was once observed drinking her own urine. Conspiracy claims In the final hours of her life, church members took McPherson not to the nearest hospital, according to investigators, but to a hospital in Port Richey where a Scientology doctor worked. Church officials have said that the investigation is part of a 15-year effort by Clearwater officials to discredit Scientology. They said McPherson was well cared for by church members but became violent and incoherent, had trouble sleeping and frequently resisted efforts to give her food, liquids and medications. The Los Angeles-based church was founded in 1954 by late science fiction writer L. Ron Hubbard.