Human rights groups have accused police of shooting dozens of people who were demonstrating against planned tax rises, some of them fatally, and abducting or arbitrarily arresting hundreds more.
Local media reported that police deployed two water cannons to the scene on Saturday, after angry protesters threatened to open the bags filled with human remains.
Officers from the Directorate of Criminal Investigations (DCI) urged people to keep calm and grant them space to investigate the discoveries, accusing protestors of impeding their investigation.
“We want to assure the public that our investigations will be thorough and shall cover a wide range of areas, including but not limited to the possible activities of cultists and serial killings,” the DCI said in a statement.
Earlier the Independent Police Oversight Authority (IPOA) said it was investigating whether there was any police involvement in the macabre deaths.
“The bodies, wrapped in bags and secured by nylon ropes, had visible marks of torture and mutilation,” the watchdog said, noting that the dump site was less than 100 metres from a local police station.
It added that “widespread allegations of police involvement in unlawful arrests, [and] abductions” meant it was undertaking a preliminary probe to establish whether there was any police connection.
Kenya’s police force is frequently accused of extrajudicial killings by human rights activists, but convictions are extremely rare. Both Human Rights Watch and Amnesty International have previously accused the force of “political interference in efforts to achieve accountability for police abuses”.
The country’s under-pressure leader, President William Ruto, has vowed that those behind the killings will be punished.
“We are a democratic country guided by the rule of law. Those involved in mysterious killings in Nairobi and any other part of the country will be held to account,” he said in a post to X, formerly Twitter.
The case is the latest disturbing such incident in Kenya.
Last year the country was left horrified after the remains of hundreds of people associated with a doomsday cult were discovered in the Indian Ocean coastal town of Malindi.
Paul Nthenge Mackenzie went on trial in Mombasa earlier this week on charges of terrorism and murder over the deaths of more than 440 of his followers. He denies the allegations.
He is alleged to have encouraged men, women and children to starve themselves in order to “meet Jesus”, in one of the world’s worst cult-related massacres.
