heroin in Geldof's body, which was at the end of the range of values at which fatalities have occurred. She was not under the influence of alcohol at the time of her death, tests revealed. Nor had she taken a significant amount of any other substances in the hours leading up to her death. Reduced tolerance ? The scientist's report notes that people using heroin regularly develop a tolerance to the drug, and such individuals can use doses that would be toxic, or fatal, to people with no tolerance. But it adds that tolerance appears to be lost fairly rapidly when users cease to use the drug, and deaths commonly occur in people who have previously been tolerant and have returned to using heroin. Fotheringham's report concluded, There is no indication that any other third party was present or involved in her death and there is no indication that Peaches intended to take her own life or harm herself in any way as she was reported to be of happy disposition and planning for the future with friends and family. Geldof was 11 years old when her mother died of a drug overdose. Kent police continue to investigate who supplied the heroin to Geldof, but no arrests have been made. CNN's Carol Jordan contributed to this report.