The search for three people - a human rights activist, his best friend and a taxi driver - has shifted to Tsavo National Park, Oldonyo Sabuk and other areas outside Nairobi, as the families called on police to expedite investigations into their disappearance.
Human rights groups, friends and families have been conducting a frantic search for Michael Njau, a rights defender working at Kiamaiko Community Justice Centre, his close friend Adan Saibu and Michael's cousin, Samuel Njau, since they went missing on Friday, April 24.
The families have visited hospitals, police stations and morgues in Nairobi, Machakos, Thika, Murang'a and Kiambu, but their search has been in vain.
Tsavo National Park and the Oldonyo Sabuk River are believed to be a dumping ground for rogue police officers involved in extrajudicial executions, and human rights groups suspect that the three may have been abducted by security forces.
On the day they disappeared, Michael and Saibu had left Nairobi for Thika in the morning to see Samuel, who worked as a taxi driver in the town.
Later in the afternoon, the three decided to travel to Nairobi using a vehicle that Samuel had hired and was driving.
But along the way, the three went missing, and the car they had hired was abandoned at Githurai 45, Nairobi.
Their phones were all activated to voicemail at intervals between 4.05pm and 4.35pm.
The Directorate of Criminal Investigations (DCI) has so far interrogated two people who are believed to have boarded the car alongside the three at Majengo in Thika - but alighted at Witeithie.
A police report sent to the DCI, which the Nation has seen, states that the vehicle - a Toyota Ractis, registration number KCX 843M, was found abandoned on April 25 at Githurai 45 near Life Restoration Centre Church.
The owner of the car, Mr Erastus Wairia, tried in vain to reach the driver, Samuel, and on tracing the vehicle using a tracking app, noted that it had been parked on the spot since 2.48pm on April 24 - the day they disappeared.
This means their phones were switched off two hours after the car they were travelling in was parked.
The vehicle was towed to Githurai Kimbo Police Station and later to DCI Thika West parking yard, where it has been dusted for fingerprints.
Officers from Thika Police Station said in the brief to the DCI that they have interviewed and interrogated a number of people.
"Call records of the missing persons reveal that Samuel's cell phone was activated to voicemail at around 1622 hours on the same day they went missing, while Adnan's cell phone voicemail was also activated at around 1631 hours."
The disappearance of the three evokes memories of last year's disappearance of Caroline Mwatha, who worked as a human rights defender at the Dandora Justice Centre.
Ms Mwatha was later found dead. Although investigators said she died from a botched abortion, her family maintains that she was murdered.
Michael's colleague told the Nation that they feared he may have been tortured or killed, since he had been on the frontline on fighting extrajudicial executions.
"He has really been campaigning against police killings and truth be told, he has received several threats. Not just him but most of us here. We handle sensitive cases touching on the most lethal police officers here. We just hope he is safe," the colleague said.
His brother, Mr Ndung'u Njau, said he was hopeful that they would be found safe; while Mr Swazuri Ali, Adan's brother, also appealed to Kenyans to report any information concerning their whereabouts.