Security officers patrolling a forest in Marlborough stumbled across the remains of dozens of butchered and boned animal carcasses.
It is the second such find in the Rai Valley area in the past four years.
BG Forestry Security officers called police when they found the carcasses of 16 cattle beasts, 12 sheep and 10 pigs on a logging skid site. Two burned-out cars were found nearby.
Security director David Birdling said the officers had followed some strange tracks to a secluded tip site where they found the carcasses.
"It looks like they have been culled on the property and this is the offal. The person who did it would probably be a home butcher."
The mixture of animals was strange, as well as the way the animals had been cut.
"It shows us that it has been a dumping and not a butchering [at the site]. All of the animals were cut and boned professionally.
"It looked like a crime scene."
It wasn't the first time Birdling and his team had come across butchered animals in Rai Valley.
Four years ago, Birdling found several cattle beasts that had been boned and butchered "professionally".
"It is a serious offence. It can breed diseases, the worst thing was we did not know what we were dealing with.
"I've been twenty years doing this work and it is a specialised job. This one threw us."
Police do not believe the two dumpings are related.
The Ministry for Primary Industries (MPI) was investigating.
MPI has been approached for comment.