An investigation into the suspected shooting of over 200 sheep in Ngapara in Otago last year has found they were killed by dogs.
The police investigation included firearm testing, the use of a forensic veterinarian and forensic testing in Australia.
Peter Stackhouse lost 195 sheep valued at $30,000, and 23 breeding rams and ewes were killed at John Dodd's farm two kilometres down the road a week later.
The initial investigation into the killings in June 2014 indicated the sheep had been shot but now police have established the sheep were killed by dogs.
Otago area commander Jason Guthrie said the investigation was unusual because of the high number of sheep attacked and the types of injuries they sustained.
Mr Guthrie said, despite a detailed inquiry, there was insufficient evidence to prosecute anyone in relation to the deaths.
Mr Stackhouse said the outcome of the investigation was disappointing.
He said the outcome raised questions about who the dogs belonged to and where they came from.
Mr Stackhouse said the fact the dogs were out there was a concern for the local farming community.