Njoro man convicted of murdering his lover four years ago

Peter Mwangi Githaiga alias John Mwangi Githaiga during a court session on July 31, 2025.
On the morning of October 13, 2020, it was a sunny day in Lusiru Location, Njoro Subcounty, where Mercy Njeri woke up bright and early to collect charcoal from Peter Mwangi. Little did she know that this would be her last walk on earth.
Mercy had left for Peter’s house at 8 am, but by 11 am, she had still not returned home. As the saying goes, bad news travels fast, and at around 11 am, Mercy’s younger brother was informed by a neighbour that his sister had died.
He rushed to Peter Mwangi’s home, where he found his sister’s lifeless body.
“Her throat had been slit open and her body was partly burnt,” he told the court.
Peter Mwangi was no ordinary person to Mercy Njeri. The younger brother revealed to the court that Peter Mwangi Githaiga, also known as John Mwangi Githaiga, had lived with Mercy for nine months, during which time the two had a child together.
However, before the tragic incident on the two had a disagreement, which led to Mercy moving out and going back to her parents' home.
Mercy’s mother confirmed that her daughter was in a relationship with Mr Mwangi. However, she opposed the marriage because, in her view, he was “not good”.
“Nevertheless, Mercy still moved in with him, and they had a child,” she said.
The family of Mercy only heard tales of how she met her untimely end. However, the neighbour of the suspect told the court that he was working on his farm that morning. At around 11 am, he heard screams coming from the neighbouring farm.
Upon arrival, he found the suspect's house ablaze.
“Other residents and I helped put out the fire; however, Mr Mwangi was not among us. After the fire had been extinguished, I saw Mercy’s body on the bed inside the house. The body was under a smouldering blanket and was partly burnt with the throat slit open,” the neighbour told the court.
According to the post-mortem report, Mercy’s body had sustained deep burns to the upper and lower limbs, and she had a slash wound to the lower neck.
"The lungs had collapsed and the blood vessels in the neck and oesophagus had been severed. The doctor concluded that the cause of death was massive blood loss due to sharp trauma to the neck”, read part of the court documents.
The police investigated the matter, and on October 16, 2020 — three days after the incident — they received information that John Mwangi was in Mathangauta, after which they placed him in custody.
Mr Mwangi denied knowing Mercy or having any relationship with her. He also told the court that, on the day when Mercy is said to have died, he was on his Mau Narok farm, where he was arrested.
While delivering his judgment, Judge Julius Nang'ea acknowledged that the suspect had raised an alibi defence, which, if proven, would strongly refute the prosecution's case. However, failure to disclose an alibi defence at an early stage may affect how much weight is given to it.
"It is emphasised that early disclosure enables the police to investigate the veracity of the defence and avoid prejudice that may otherwise be caused to the prosecution. The alibi defence is therefore not credible and does not displace the prosecution evidence. It appears to be an afterthought, as no notice was given to the prosecution as required by law,” said the judge.
He further stated, "I find that the prosecution proved the charge beyond reasonable doubt, and the accused is accordingly convicted."
He will be sentenced at a later date.