Police in Mathira, Nyeri County, are investigating the murder of two women linked to a suspected serial killer who attempted to hide behind a claim that two detectives had plotted to assassinate the area MP.
On February 12, Mathira MP Eric Wamumbi was alerted by a local official that he was the target of an assassination. The intelligence came from Thiuu Assistant Chief Justus Gathecha who informed the legislator that the would-be assassin had shared information about the alleged plot.
Joseph Njoroge Weru had reported to Mr Gathecha that he had been hired by persons suspected to be Directorate of Criminal Investigations (DCI) officers from Mathira East sub-county to assassinate the MP.
This report was the start of a comic-tragedy script that would in the end expose Weru as the suspect in the murder of Ms Beatrice Nyawira, whose body had been found in Tetu sub-county on February 12, the same day the MP was being tipped off about the alleged murder plot.
With the “leak” on the planned hit, Mr Wamumbi rushed to Karatina Police Station and filed a formal complaint that he had reliable information of a plot to kill him. The MP’s report was recorded as OB number 64 of February 12.
When the incident report was circulated to police command centres, Central region DCI boss Abraham Mugambi ordered immediate investigations.
Mathira MP Eric Wamumbi addresses journalists in Nyeri town on October 22, 2025.
Photo credit: File
“I detail a team of senior police officers from both Central Region and Nyeri County to partner in extracting the truth out of the claim fastest possible,” Dr Mugambi wrote in his incident command signal on the morning of February 13 .
In a communication to his juniors, Dr Mugambi stressed that the complaint by the MP “was by no means a petty report...it was explosive”. “It is not always that an MP walks into a police station to report fears on his or her life and quoting an assistant chief as the authority behind the claim,” Dr Mugambi wrote.
A source in the police station confided in the Nation that the matter caused ripples since it had also attracted the attention of the presidency and police headquarters. The MP is a close ally of President William Ruto.
A senior security delegation was dispatched to reassure the Wamumbi family at their village home. The assistant chief and the self-proclaimed hired assassin were summoned to Karatina Police Station.
Meanwhile, all DCI officers attached to the station were ordered to report on duty without fail on the morning of February 13. The brief informed them that they were required to participate in a joint operation.
The investigators who were accompanied by both Dr Mugambi and Regional police boss Jasper Ombati then staged an identification parade at the Karatina Police Station.
“The said assassin for hire was present and so was Mr Wamumbi,” reads the identification parade report.
Weru identified Corporal Richard Boen and Constable Jesse Muriki, both serving as DCI officers in the station, as the ones who had hired him to kill Mr Wamumbi.
The two officers were immediately detained for interrogation and possible booking for the offence of planning to commit murder.
Weru was congratulated for being a law-abiding citizen who had refused to participate in the “murder” and instead alerted security agencies.
Man who had been questioned over the killing of a woman, falsely accused DCI officers of hiring him to assassinate Mathira MP Eric Wamumbi.
Photo credit: File | Nation Media Group
But in the interrogation room, detectives poked holes into Weru’s statements. His version of events raised more doubts. And then a dark secret emerged.
“It was established that on January 29, 2026, a report had been made by Ms Annah Mugure at Karatina Police Station Vide OB number 62/29/01/2026 at 1918 hours that her sister, namely Beatrice Nyawira, aged 23, had gone missing,” the preliminary investigations report by Dr Mugambi reads. It adds that officers Boen and Muriki accompanied Ms Mugure to her missing sister’s house and it was established that the missing woman was living with Weru.
Weru was found resting in his bed by the two officers and they arrested him. He was interrogated at Karatina Police Station and released the same day.
“It became apparent that Mr Weru was being creative in trying to escape the ongoing investigations about the murder of Ms Nyawira by invoking the name of Mr Wamumbi in an assassination plot said to be planned by the two officers who were on his case,” reads the DCI report of February 16.
The report notes that Mr Wamumbi, “though devastated, he has agreed he is satisfied by the turn of events including thanking the officers for the genuine concern and speedy investigations”.
Weru was subsequently arraigned in court on February 16 and the DCI was granted 30 days to continue holding him at Othaya Police Station pending conclusion of investigations that include suspicion of being behind three more murders.
Investigations have revealed that Weru was a possible serial killer targeting women, with the second victim already identified.
Mary Murutuni, 28, a mother of three, had moved from Mukima in Nanyuki to Narumoru town, where she worked at a boutique and lived alone in a rented house. She went missing on January 17. When relatives went to Narumoru looking for her, they were told she had left in the company of a man. The family reported her missing at Castle Police Post in Laikipia East.
Neighbours said a man identified as Joseph Weru had stayed at Mary’s house for three days shortly before her disappearance. Mary had separated from her husband in Laikipia about a year earlier and had since allegedly begun a relationship with Weru.
Her body was discovered on January 19, dumped in a farm along the Karogoto River in Karatina. Police said the body was found partially submerged in water and bore visible injuries.
Police are piecing together the profile of Weru, a 23-year-old from Rwamara-Karogoto village in Nyeri County. He is depicted as a man who operated discreetly and those who have interacted with him in the past say he introduced himself as a Kenya Defence Forces serviceman in Nanyuki. They say that he showed them several photographs of himself posing with police patrol vehicles
DCI officers have identified the Ithekahuno Maingirano–Macemanio forest near River Gura as a possible dumping ground for his victims.
