Acting Detective Sergeant Liz Williams said the stock's ears were all cut off ''and that's potentially an attempt to avoid identifying the sheep, which makes it suspicious, that those distinguishing features have gone.''
Removing any earmarkings or tags made it difficult to trace the owner of the sheep.
Stock agents yesterday said the value of each animal would be between $80 and $100.
The carcasses were found earlier this week by the owner of the farm where they were dumped. The offenders would have needed a 4WD vehicle to access the spot and the animals had probably only been dumped a few days before they were found.
Acting Det Sgt Williams said. Police were investigating two main possibilities. The first was that the stock had been stolen and butchered and the second was someone had butchered their own stock and illegally dumped the carcasses.
''Whoever has done this knows how to butcher; it's quite a professional job. All carcasses were skinned down to the foot, the empty pelt had the legs tied back together and the guts were thrown back in for ease of handling.''
''It would have been a lot of work for one person so we're looking for more than one offender,'' she said. Most of the dumped animals were 2-tooths and at least one was in lamb, as a dead lamb was among the strewn carcasses.
''The stock had been shorn recently and there were enough to fill up a stock crate, so they might have been penned up ready to be transported or perhaps taken from a truck on its way somewhere.
''A few pelts had orange raddle crayon marks, so they were already marked for something, either for theft, for sale or for the works.''
She believed they were taken from somewhere in Central Otago and it appeared the offenders had backed a vehicle up to the edge of the bank and thrown the carcasses over.
Police wanted to hear from anyone with information about the incident or from farmers with missing stock. Acting Det Sgt Williams had emailed more than 100 property owners registered in the anti-poaching scheme in Otago, but so far, nobody had reported missing this number of stock.
''Someone out there must have information - maybe they've heard of someone being offered cheap meat and people should be concerned about where that meat is coming from.
'' If it's stolen you know nothing about the origins of the meat - whether the sheep had been drenched lately, for example,'' she said. People with information could call anonymously on 0800-555-111 or contact Alexandra police, Det Sgt Williams said.
