Kenya's police watchdog said it is investigating whether there is any police involvement in the gruesome discovery of mutilated bodies dumped in a Nairobi rubbish tip.
The Independent Police Oversight Authority (IPOA) is also looking into claims of abductions and unlawful arrests of demonstrators who went missing after widespread anti-government protests.
Police initially said the severely mutilated bodies of six women tied up in plastic bags were found on Friday dumped a garbage site in an abandoned quarry in Mukuru, in the south of the capital.
The IPOA said in a statement later that the remains of at least nine people had been recovered, seven of them female, and called for swift investigtions to identify them.
"The bodies, wrapped in bags and secured by nylon ropes, had visible marks of torture and mutilation," it said, noting that the dumpsite was less than 100 metres (yards) from a police station.
Kenyan police are under sharp scrutiny after dozens of people were killed during the demonstrations last month, with rights group accusing officers of using excessive force.
National police chief Japhet Koome, the target of much public anger over the protest deaths, has resigned after less than two years in the post, Kenya's presidency announced Friday.
He is the latest head to roll as President William Ruto scrambles to contain the worst crisis of his rule, triggered by deeply unpopular proposed tax hikes.
Crowds that gathered on Friday at the site where the bodies were found were chanting "Ruto must go", the slogan of the wave of protests led by young Gen-Z Kenyans.
Kenyan police are feared and face frequent allegations of extrajudicial killings but are seldom convicted.
Images on local television showed people using ropes to heave sacks containing the human remains from rubbish-strewn water in the quarry dumpsite.
"As the police investigations unfold, IPOA is keenly independently undertaking preliminary inquiries to establish whether there was any police involvement in the deaths, or failure to act to prevent them," the agency said.
The Directorate of Criminal Investigations said preliminary investigations suggested all the victims had been killed in the same manner, without elaborating.
The Office of the Director of Public Prosecutions also highlighted the location of the bodies so close to a police station and said was "deeply concerned" about the discoveries "which point to a grave violation of human rights".
It has directed the police to submit the results of their inquiry within 21 days, and also urged state agencies including the IPOA to expedite their investigations into reports of enforced disappearances and deaths allegedly committed by police.
The Kenyan Human Rights Commission, a non-governmental organisation, said it was also urging a "comprehensive investigation" to determine the cause of the deaths and identify those responsible.
"The perpetrators must be held accountable," it said in a post Friday on X. "Kenya Kwanza regime, led by William Ruto, must take accountability for this heinous crime."
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.
There have been few examples of police being held to account, although Ruto has pledged in the past to put an end to violence and illegal practices by law enforcement officers.
Kenya's parliament established the IPOA in 2011 to provide civilian scrutiny of a powerful institution also reputed to be among the country's most corrupt.
Activists largely defend the IPOA's record, saying police often frustrate investigations by refusing to cooperate.
Koome's resignation followed Ruto's announcement on Thursday that he was sacking almost his entire cabinet, his latest bid to try to mollify the young protest movement.
