still, it's debated:
http://www.channel4.com/news/articles/society/law_order/why+is+madeleines+hair+so+important+/792847
"
Q. Can they tell whether Madeleine was alive or dead?
A. The DNA samples themselves cannot tell us whether they came from a live or dead source - but they can be used to identify whether or not they came from Madeleine. Alan Baker, a forensic scientist who has given expert evidence on the subject of DNA in court cases said:
"DNA itself would not tell you if that person is dead or alive. If it was associated with bone fragments or a piece of tissue, that is another story."
Some experts argue that the state of decomposition of the hair samples themselves, could show whether they were taken from a living person or not. Hair taken from a deceased person decays in a different way to hair from a live person, but this could be affected by other factors - such as the temperature of the surrounding air."
i should be asleep and I promised to stay away from computer for 24 hours, oh dear