JOHANNESBURG, South Africa (AFP) — South African police are racing to crack the killings of at least seven women whose bodies have been found east of Johannesburg in two months, the latest on Tuesday.

The country has one of the world’s highest homicide rates, but the discovery of the women’s bodies, partially naked and battered, has sparked fresh anxiety and raised fears that a serial killer or group of killers may be operating in the area.

Five bodies were recovered in just one week in the Ekurhuleni municipality, police said.

“We are still investigating whether we are dealing with one perpetrator or a group of men that are behind the murders of these women,” police spokeswoman Athlenda Mathe said, describing the discoveries as “concerning”.

Gender-based violence is endemic in South Africa, where one in three women experiences physical or sexual violence during her lifetime, according to the United Nations.

The first victim, a 37-year-old woman, was found naked and bound with cable ties on July 15, police said. A suspect was arrested two days later.

A second woman, 32, was found partially clothed on August 24, while a third was discovered naked and in an advanced state of decomposition on September 10.

The fourth victim, 38-year-old Elizabeth Moselakgomo, left her eight-year-old daughter at home to go for a jog and never returned. Her body was found on September 12 behind a hotel, police said.

Moselakgomo’s disappearance drew public attention after fellow runners launched a social media campaign to find her, which led to the discovery of more bodies.

President Cyril Ramaphosa on Tuesday said “no stone will be left unturned” to solve the killings, acknowledging “these incidents are causing fear and uncertainty in our communities, and especially among women”.

Acting police minister Firoz Cachalia described the discovery of the bodies as “deeply disturbing”.

Amnesty International South Africa said the discovery of the bodies was “just another horrific reminder that women in South Africa are not safe”.

South Africa, a nation of 62 million people, has some of the highest rates of violence against women and children in the world, according to UN Women.

At least 60 people are killed each day in South Africa, many linked to turf battles between gangs involved in drugs and illegal mining.