He is a son of Mr Nicholas Njoroge, who was killed alongside his family.

Detectives investigating the matter told the Nation on Friday that Lawrence’s phone was switched off on Tuesday night in Naivasha, Nakuru County.

This is the same night that killers raided their rural home in Kagongo Village, Kiambu, and hacked his father to death alongside his mother Ms Wanjiku Njoroge, his brother Mr C. Njoroge, his cousin Mr Maxwell Njoroge, and their farmhand.

Kiambu County Commissioner Wilson Wanyanga said the son has been missing since the night of the murders and efforts to trace him have been futile.

Track him using his mobile phone

“Nothing has been heard of him since the murders happened. We have tried to track him using his mobile phone but this has not been successful because his phone signal shows it was switched off on the same day the bodies of his family members were recovered inside their house,” said Mr Wanyanga.

“Police records show that his mobile phone was last switched off in Naivasha, Nakuru County,” said Mr Wanyanga.

Mount Kenya University head of Marketing and Communication Boniface Murigi, when contacted by the Nation, said he could not comment about the issue given no family members had reached out to the institution.

Lawrence’s disappearance for nearly a week, police said, had further complicated the investigation because detectives investigating the matter had always believed that he had escaped death by a whisker because he had just reported back to school a day before the attack.

Two other children of Mr Njoroge, who were in school when the killings happened, are safe.

Detectives on Friday told the Nation they had narrowed their investigations down to either succession wars, family jealousy or ritual killings as the motive of the killings.

Meanwhile, police said the scene of the crime has been cordoned off and will be guarded by armed officers round the clock for one month.

Investigators from the homicide department spent the better part of Friday combing the area trying to piece together the evidence.

Kiambu County  Police Commander Ali Nuno, who alongside Mr Wanyanga led the investigations,  told the Nation that although they have not made any arrests, they are following up crucial leads and he believes that they will arrest the suspects by Monday next week.

Make a breakthrough

“We have made crucial leads and, in the next two or three days, we are going to make a breakthrough and arrest the suspects,” Mr Nuno told the Nation in an interview on Friday.

Detectives say going by the fact that nothing was stolen from victims of previous murders affecting other family members, there must be something sinister within the family.

The investigations have been narrowed down to close family members as well as the extended family, the Nation understands.

In 2016, Allan Njire, a brother of Mr Njoroge, was also shot by unknown assailants while parking his car in Kiambu. He was in the company of his now-deceased brother.

Mr Njire survived the murder plot and now walks with a limp.

And in 2017, another brother of Mr Njoroge, identified as Mr Kenneth Mwangi, was hit from behind with a blunt object by unknown people. He died instantly.

Mr Njoroge's niece was also stabbed to death.

The latest incident has thrown the sleepy Kagongo Village into shock with neighbours avoiding talking about the killings openly.

Mr Njoroge, 54, had jetted in for Christmas on December 4 from the USA. He used to come to Kenya once or twice a year, neighbours say.

His wife, who was also killed in the attack, was a nurse at the Wangige Level Four Hospital within Kiambu County.