Searches are under way for the weapon gardaí believe was used to fatally assault a 36-year-old Polish man in Letterkenny.
Sebastian Adamowicz was hospitalised with severe head injuries on Wednesday 1 November.
Gardaí believe the weapon will provide vital information.
They were called to 15 Sylvan Park, where Mr Adamowicz had lived with four other Polish people for a few years, at about 4.50pm on 1 November.
He was taken by ambulance to Letterkenny University Hospital where he died as a result of his injuries shortly after midnight.
Detective Inspector Pat O'Donnell said the Garda Technical Bureau carried out a full examination at 15 Sylvan Park and a number of samples and items were taken away for testing.
A search of the house and surrounding area has also been carried out and a trawl of CCTV is continuing.
Gardaí are now appealing to anyone who may have dashcam footage from the area to contact them.
They are asking anyone who was in the Sylvan Park area between 10am and 6pm on Wednesday 1 November to come forward.
Gardaí said there would have been a lot of visitors in the area that day, the day after Halloween, along with taxi drivers and delivery people who may be able to help the investigation.
Detective O'Donnell said they have already interviewed a number of people including those who lived in the house with Mr Adamowicz.
Mr Adamowicz was a single man who worked in Ireland for a number of years but had not been employed in recent times according to the detective who said that he and his friends would have been well known in the area.
Mr Adamowicz's mother and father travelled from Poland to Donegal when they were told of his injuries but he had died when they arrived.
Det O'Donnell said they were distraught, he had spoken to them through an interpreter and is keeping in close contact with them.
