The leader of Liberia's transitional government, Gyude Bryant, has promised to use the death penalty against anyone found guilty of sacrificial killings.
In January there were large protests against ritual killings
During an address on state radio Mr Bryant said people were killing in the belief it would make them successful, rich, or the next president.
A BBC correspondent in Liberia says the number of ritual murders are growing.
Sacrifices have been reported in three of Liberia's counties - the latest involving beheading and organ removal.
"We'll find you, we'll arrest you, we'll prosecute you and let me say again to everybody, if the judge passes down a ruling to say you must die by hanging, I will hang you," Mr Bryant said. "I will sign the death warrant without batting my eye."
The BBC's Paul Welsh in Monrovia says that almost two years of peace in Liberia have done little to help ease the poverty in what is one of the world's poorest nations.
Elections for the first president since Charles Taylor left the country are due in October, which, our correspondent says, is the likely reason for the increased number of ritual killings.
Human parts such as genital organs are believed to offer supernatural powers, especially by aspiring politicians and so the number of alleged ritual killing rises in the run-up to elections.
According to local media reports the latest such killing, which occurred in the northern Bong County, involved a female who was beheaded and had her genital organs removed.
"If you killed because you want to make a sacrifice to be president or senator, you fool yourself," Mr Bryant said. "Stop ritualistic killings, it will not pay you anything, it will not make you rich, it will not give you jobs."
In January extra United Nations peacekeepers had to be sent to south-eastern Liberia following violent protests over alleged ritual killings.