Five people have died after drinking a poison potion in a Santeria “power” ritual, police in the southern Mexico state of Oaxaca said Wednesday.

Iván García Alvarez, the Oaxaca state police chief, said four men and one woman died after drinking a mix of substances he did not specify.

He said they were involved in Santeria, a faith that began in Cuba when African slaves blended Yoruba spiritual beliefs with Roman Catholic traditions.

García Alvarez said the victims mixed the potion themselves and drank it “to acquire some certain kind of powers.” He said the deaths at a home in Oaxaca city are being investigated as a group suicide.

García Alvarez said the people were involved in Santeria and when they drank the potions, “the only thing that happened was they died of poisoning.”

Their bodies were found Saturday at a house on the outskirts of Oaxaca city with no outward signs of injuries. The victims were apparently related, and ranged in age from 18 to 55.

Prosecutors said at the time that tests were being performed to identify the substances found in the house.

In the past, shamanic and other rituals in Mexico have involved toxic or hallucinogenic substances like Devil’s Trumpet, or jimson weed, and venom from the Colorado River toad, but it was not known what substances were involved in the most recent deaths in Oaxaca.

However, Santeria has been implicated in other cases of skullduggery in Mexico.

In 2018, a man from a suburb of Mexico City confessed to killing at least 10 women, and claimed to have sold the bones of some of his victims to practitioners of Santeria. The suspect said he sold the bones to a man he met at a bus stop.

Parts of the man’s confession may have to be taken with a grain of salt; he initially confessed to killing 20 women, but was able to provide details — names and description of the victims — in only 10 cases.

According to the U.S. Department of Justice, which studied the Caribbean religion to better understand its thousands of devotees incarcerated in American prisons, Santeria requires devotion to the “orisha” spirits, which takes four main forms: divination, sacrifice, spiritual mediumship and initiation.

“In prisons, devotees build altars with discarded cereal boxes and provide sacrificial offerings of apples, oranges, coffee, cigars, and pigeon feathers. One inmate also made a candle out of butter that had turned sour,” the Justice Department said.

This week’s poison deaths come just weeks after police said 50 people died in Angola after being forced to drink an herbal potion to prove they were not sorcerers.  A local councilor accused traditional healers of administering the deadly concoction.

“More than 50 victims were forced to drink this mysterious liquid which, according to traditional healers, proves whether or not a person practices witchcraft,” she said.