Ukrainian police say they have arrested three men and a woman on suspicion of murdering six people and eating their flesh.
Police officials in the central town of Zhytomyr said the group's last victim was an 18-year-old girl.
"They killed a young woman in a forest and then cut out fleshy parts of the body and ate them. This is horrible," a police spokeswoman told the Reuters news agency.
The last high-profile case in the region where cannibalism was a factor was that of Russia's serial killer, Andrei Chikatilo.
He killed 53 women and children in a prolonged campaign of serial murder which began in 1978.
Chikatilo - who grew up believing his older brother been kidnapped and eaten during the great Ukrainian famine of the early 1930s - mutilated some of his victims by gnawing at them.
Black magic books
In what is believed to have been a Satanic ritual, the suspects killed the girl with two knife thrusts to the heart, local interior ministry representative Viktor Kurbatov was quoted as saying by the French news agency.
The suspects are said to have then scalped the young woman, boiled her decapitated head and to have eaten it before cutting out her organs.
Several days afterwards, police arrested the suspects when they were waiting to meet the girl's parents from whom they had demanded a $3,000 ransom.
One policeman was injured during the operation.
Police found "several books on black magic" at the house of the one of the suspects, a 53-year-old man, the official added.