An autopsy is to be carried out today but gardaí were not certain if the man in his late 40s simply fell or died in suspicious circumstances.
They were alerted by a call at around 5pm yesterday, after the man is believed to have been found by other residents.
He was pronounced dead a short time later and the scene at the building on Harbour Hill was preserved. However, it was not clear if the man had suffered a fall or a health issue, or if any other person was involved.
The local coroner was notified, and assistant State pathologist Margot Bolster examined the man’s remains last night at the scene.
Gardaí were awaiting the outcome of her preliminary examination before determining whether or not the death was suspicious.
However, this might not be fully decided until after the autopsy results are known.
In the meantime, inquiries were taking place last night and several people were interviewed by gardaí.