A man reacts after seeing a body of an unknown person retrieved from a dumpsite in Mukuru slums, in Nairobi, Kenya, July 12, 2024. (Photo/Reuters)

Kenya's under-fire police have pledged a "transparent" investigation following the discovery of eight female bodies dumped in a Nairobi garbage site.

Police chiefs said they were pursuing possible links to cults, serial killers or rogue medical practitioners in their investigation into the macabre saga, which has horrified and angered the nation.

The mutilated and dismembered bodies, trussed up in plastic bags, were hauled out of a sea of floating rubbish in an abandoned quarry in Mukuru, a slum area in the south of the Kenyan capital.

The discoveries have thrown another spotlight on Kenyan police and added more pressure on President William Ruto, who is struggling to contain a crisis over widespread anti-government protests that saw dozens of demonstrators killed.

Acting national police chief Douglas Kanja said six corpses were found in Mukuru on Friday and more body parts were retrieved on Saturday, with preliminary investigations revealing that all were female.

"They were severely dismembered in different states of decomposition and left in sacks," Kanja told a press conference, describing it as a "heinous act".

He said police were committed to conducting "transparent, thorough and swift investigations" adding that they aimed to wrap up their inquiries in 21 days.

Kanja, who was appointed only on Friday amid the fallout over last month's protest bloodshed, also said that all officers at the police station located near the quarry had been transferred.

Police watchdog probe

Kenya's police watchdog, the Independent Police Oversight Authority (IPOA), had said on Friday it was investigating whether there was any police involvement in the dumped bodies, noting that the dumpsite was just 100 metres from the police post.

The IPOA also said it was looking into claims of abductions of demonstrators who went missing after last month's protests.

But it did not make any link to those missing and the dumped bodies.

Mohamed Amin, the head of the Directorate of Criminal Investigations, said the ages of the victims ranged between about 18 to 30 and that all had been killed and butchered in the same manner.

He said police were looking into a number of hypotheses.

"Are we dealing with a cult that is associated with criminal activities, are we dealing with serial killers?" he said at the press briefing alongside Kanja.

"We even could be dealing with rogue medical practitioners."

Cult massacre

Kenya was left reeling last year by the discovery of mass graves in a forest near the Indian Ocean coast containing the bodies of more than 400 members of a doomsday sect, one of the world's worst cult-related massacres.

On Monday, self-proclaimed pastor Paul Nthenge Mackenzie went on trial on terrorism charges along with 94 co-defendants over the deaths, accused of inciting his followers to starve themselves to death in order to meet Jesus.

He and the other accused also face charges of murder, manslaughter and child cruelty in separate cases over what has been dubbed the "Shakahola forest massacre".

Some people on social media have described the dead women in Mukuru as victims of femicide.

"This horrific act is an urgent reminder of the ongoing battle against gender-based violence that we must confront as a nation," Kenya's State Department For Gender and Affirmative Action said in a statement.

The country's law enforcement services are already under scrutiny over the protest deaths, with rights groups accusing police of using excessive force.

Kanja took up his post only this week after national police chief Japhet Koome resigned in the face of public fury over alleged police brutality during the demonstrations.

A total of 39 people were killed and more than 630 injured during the unrest, Kenya's national rights commission said earlier this month.

Kenyan police are often accused by rights groups of using excessive force and carrying out unlawful killings, especially in poor neighbourhoods.

They have also allegedly run hit squads targeting people such as rights activists and lawyers investigating alleged abuses by police.

Few police have been held to account, although Ruto has pledged in the past to stamp out violence and illegal practices by law enforcement officers.