Yaounde, Cameroon (CNN) -- Michele Mbala Mvogo, a 17-year-old high school student, left home to go to school one morning, and she never came back.
On Friday, police found Michele's corpse with four other bodies dumped outside a kindergarten school. Fighting back tears, Deborah Ngoh Tonye described what was left of her sister's gruesome corpse. Someone had removed Michele's genitals, tongue, eyes, hair, and breasts.
Michele's bizarre murder is believed to be part of a wave of killings linked to occult rituals that has triggered panic in Yaounde, the capital city of more than 2 million people in the West African nation of Cameroon.
In the past two weeks police have found 18 bodies dumped along the streets. Authorities said all of the bodies had been mutilated. Officials have not said if the female victims among the 18 bodies had been raped.
State security officials said Tuesday the bodies have been identified. The victims, who are between the ages of 15 and 26, are mostly Yaounde high school students, police said. They said a number of suspects have been arrested in the case, but so far no one has been charged.
State intelligence officials have launched an investigation to track down the killers, said Communications Minister Tchiroma Bakari.
In some regions of the country, traditional healers claim eyes, genitals, tongues and other organs have mystical powers. Some occultists believe such organs hold the keys to gaining wealth and other good fortune.
Until the 1970s, ritual killings were a common cultural practice in Cameroon, before education became more widespread. Signs of its gradual resurgence beginning last year have shaken much of the city.
The fear is most noticeable as evenings approach. Many families lock themselves indoors beginning in the late hours of the day, while young men band together in vigilante groups, roaming the streets looking for killers.
Police have shut down dozens of bars that are suspected as hangouts for criminals. Security officials warn pedestrians, especially girls, to walk in groups.
Fears about occult groups and human organs gained strength in late 2012 when Health Minister Andre Mama Fouda fired a laboratory technician and four mortuary attendants. They admitted to trading organs harvested from dead bodies stored in the mortuary of the state regional hospital in Douala, Cameroon's largest city.
In Yaounde's public hospitals, dozens of relatives have complained to administrators about mutilated corpses, said the minister of public health.
Taking organs for such uses represents a "gross violation of human rights," said Cameroon human rights advocate Rosine Djoumessi Masonwa. Local authorities must work "to end the mutilation of human bodies through strong laws and widespread education programs."
As she grieves for her sister, Tonye, like so many others, is frightened and worried that more isn't being done.
"There is laxity in the forces in ensuring security in the capital," she said.