GARDAI have launched an investigation into the death of a 17-year-old girl in Letterkenny earlier today.
The teenager was taken to hospital after feeling unwell at a nightclub in the town last night.
She was able to walk to the ambulance and she appeared to be fine when being treated at Letterkenny General Hospital.
However, just after 6.30am she suffered a suspected heart attack and she was pronounced dead some time later.
Relatives of the girl are said to be distraught at her death.
The girl comes from a well-known and highly respected family in the Co Donegal town.
It's understood a post mortem will take place later today.