A police sting intended to deter grave robbers has led to the arrest of eight who steal skulls to be sold for use in rituals.

The Associated Press reported that police were alerted by families who had noticed that their loved one's graves had been tampered with near Gabon's capital. Authorities staked-out the cemeteries, and arrested eight suspects for the stealing nine skulls and a femur bone. Police told the AP they suspect there are many more human remains stashed and hidden in the suspects' homes.

The alleged ringleader, Jean Martin Moussavou, told local TV reporters that the group had been involved in the taboo industry since 2004. Makers of traditional medicines and fetishes ordered supplies, and Moussavou knew where to get them. He said he and his crew would rob cemeteries in the night.

Moussavou said each scull would fetch 250,000 Central African francs, roughly $620.

The skulls and bones were ground into a powder to be used in potions and amulets, which are believed to give power and strength to the consumer or wearer.

It is also used in a common religious initiation ritual, called Bwiti, in which the eboga plant, sometimes called "the plant of truth," is consumed to invoke hallucinations, or visions. The Bwiti ritual is a three day event that happens when a child is 8 to 13-years-old. Once completed, the inductee is part of the religious group and ready to enter adulthood.

The AP reported, though, that many who are involved in the ritual were not aware they were consuming a deceased person's bones.

If the grave robbers are convicted, they face two to five years in prison.