How prosecution proved former Riruta MCA Samuel Njoroge murdered his wife

Former Nairobi MCA Samuel Ndung'u Njoroge who colluded with three accomplices to abduct, torture and kill his wife Lucy Njambi in Kiambu County six years ago is now awaiting sentencing after he was convicted of murder.

Njoroge, the former Riruta MCA was found guilty of the capital offence alongside two accomplices Joyce Njambi Mungai and Wilson Mwangi Munyua. 

The trio killed Njambi on January 24, 2018, by torturing and dousing her body with sulfuric acid, alongside the third accomplice who has never been arrested. 

According to the prosecution, Njoroge had accused the wife of infidelity and had sworn “to do something to stop her from sleeping with uncircumcised men". 

Justice Joel Ngugi of the Court of Appeal convicted the trio and ordered Njoroge and Munyua be remanded at the Nairobi Remand. At the same time, Ms Mungai was placed in custody at the Langata Women's Prison until Friday next week when the court will resume hearing before setting a date for sentencing.  

The judge also ordered a victim's Impact Assessment Report to be presented in the subsequent hearing. 

The murder 

A Good Samaritan found Njambi screaming while lying naked and scalded at a coffee farm along Kiambu Road. The Samaritan rushed her to the County's Referral Hospital for first aid and assessment.  

According to a doctor’s report, she had suffered severe burns on her entire body which later turned out to be the effects of a highly corrosive acid. Njambi was later transferred to the Kenyatta National Hospital (KNH) but did not survive. 

"The prosecution advanced a theory that Njoroge and his accomplices staged an abduction where he and the deceased appeared to be the victims but the sole aim was to lure, capture, humiliate and ultimately murder her, creating what they thought was a perfect defence for (Njoroge),' stated Justice Ngugi.   

The judge was satisfied that the prosecution had perfectly proven the theory, adding that the best-laid plans of mice and men often go awry. 

The Office of the Director of Public Prosecutions (ODPP) called 38 witnesses to prove its case against the three convicts. Among them were eyewitnesses who splashed water on the deceased after discovering she was suffering from burns, and a few of her relatives who spoke to her at the Kiambu Hospital.

Njambi, an orphan, shared the contacts of her grandmother who reached out to family members and informed them of her predicament. The relatives proceeded to the Kiambu Hospital and spoke to her minutes before she passed away. 

Lucy Njambi was tortured and killed by her husband, former Riruta Ward Member of County Assembly Samuel Njoroge and three other accomplices on January 24, 2018. (Photo: X Collage)

Her dying declarations 

The ODPP referred to her conversation with her family members as ‘the victim’s dying declarations’. These are statements made by a person who is on the brink of death, providing the alleged cause of circumstances surrounding his or her impending demise. 

She had hinted to at least seven people including Dr. Jackline Rigii who attended to her at KNH, that her husband was trying to kill her and was responsible for her suffering before death.

Coupled with circumstantial evidence, the ODPP embarked on its bid to incriminate Njoroge, Joyce Njambi Mungai and Wilson Mwangi Munyua of murder. 

Justice Ngugi noted that the evidence of these seven witnesses proved that Njoroge harboured a motive to kill her. According to the evidence presented, Njoroge was a scorned husband in search of revenge against a woman he felt had betrayed him after giving her everything.

The deceased had visited her aunt in Kawangware severally where she shared about her husband's physical and emotional cruelty and later sent a text to her urging her to take care of her four-year-old son if she died. 

Other witnesses

The star witnesses in the case were police officers who investigated the case, including Corporal Catherine Gatheca who recovered a bottle containing the remnants of the acid from Njoroge's car.

Eunice Wamuyu Njogu, a scientist at the government chemist tested and identified the substance presented by Cpl. Gatheca.

Njogu had received a pair of faded jeans, a pair of white socks and a blouse worn by the deceased, surgical gloves, two carrier bags and a piece of used cello tape, which had been collected at the scene by the Directorate of Criminal Investigations (DCI) detectives.

She conducted her analysis using DR Spectrophotometry techniques and concluded that the substance which was also present in the items collected at the scene was sulfuric acid.

Benjamin Mburu, Joyce Njambi Mungai’s former high school teacher testified that she called him on January 22, 2018, asking how to buy sulfuric acid. After noticing that Mburu was shocked, she assured him it was for cleaning rust from metals but the call was terminated before the conversation ended.

He later received a call from a man who turned out to be Njoroge, who asked about the same substance. 

Jonathan Limo, a police liaison officer at Safaricom Kenya Limited generated call data records (CDR) for the convicts.

He established that Ms Mungai and Njoroge spent time together, moving from one place to another within Nairobi before proceeding to Thindingua in Kiambu County where the deceased was abducted.

The data also showed that Munyua and Njoroge were in constant communication that night despite insisting that they did not know each other

"The upshot is that applying the appropriate principles of circumstantial evidence to the present case, this court can truly say that the circumstances taken cumulatively form a chain so complete that there is no escape from the conclusion that within all human probability, the crime was committed by the accused persons," Justice Ngugi adduced.

Hon. Justice (Prof) Joel Ngugi being sworn in as Judge of the Court of Appeal in September 2022. (Photo: Judiciary)