Officers said the local coroner has been notified and a post-mortem examination will be arranged.
A man arrested last week in connection with the suspected murder of schoolboy Kyran Durnin has been found dead.
The man was released without charge last Friday as an “intrusive” search at a home in Co Louth concluded.
Police said that emergency services were contacted following the discovery of a man’s body at a house in Drogheda on Tuesday.
The man was aged in his 30s.
Officers said the local coroner has been notified and a post-mortem examination will be arranged.
The outcome of the post-mortem will determine the course of the investigation, gardai said.
It is understood from early indications that it is a personal tragedy.
Subscribe or register today to discover more from DonegalLive.ie
Buy the e-paper of the Donegal Democrat, Donegal People's Press, Donegal Post and Inish Times here for instant access to Donegal's premier news titles.
Keep up with the latest news from Donegal with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.