Nigerian police say they have found a further 33 bodies in addition to the 50 already uncovered in fetish shrines in south-eastern Anambra state.
A traditional cult reputed to carry out ritual killings is thought to have carried out the murders.
Some of the corpses had hands, genitals or heads missing.
Police have displayed skulls - and five men of the 30 or so people arrested in connection with the murders - to correspondents in the capital, Abuja.
"Police are concerned about how the headless bodies found their way into the shrines," said deputy police chief Sunday Ehindero.
However, a spokesman for those arrested denied any involvement in the killings.
"Since I have been there, for two years, I have not seen anybody killed by these people. Rather, the shrines kill," said Collin Obi.
He said bodies had been brought to the Okija shrines by family members.
Mr Ehindero said groups involved in disagreements had gone to the shrines to take part in black magic rituals.
"What we are saying is that we found there is a parallel court," he said.
Police found the shrines after being tipped off by a local villager in Okija who reported the priests had eaten the flesh of some of their victims.