Last weekend, a homeowner awoke to find the front of their home in Clonmany covered in oil. The incident occurred between 10pm on Friday night, August 12 and Saturday morning, August 13.
The incident was reported to gardaí.
Garda Niall Maguire said: "This is a pretty unusual occurrence and the motivation is not apparent to us or to the householder. The householder is to a complete loss as to why this occurred."
Gardaí are seeking the help of the public and if you can help or have any information in relation to the incident, you are asked to please contact gardaí in Buncrana on 074 93 20540.
Gardaí at the station will pass on any information to the investigating team.
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.