Nominated senator David Sankok's son had refused to report back to Kericho High School before he shot himself dead using his father's gun.
The 15-year-old, Memusi Sankok, was expected to report to school last week but was reportedly not keen on doing so which triggered a quarrel between him and his father.
Memusi is said to have taken the gun from his father's bedroom at their Ewaso Nyiro home in Narok, and shot himself dead.
Narok County DCI boss Mwenda Ethaiba said Memusi's death followed a fight with his father after the teenager refused to report back to school.
The MP is said to have insisted that his son should report back to Kericho High and even went ahead to give him money for shopping and transport.
In a WhatsApp post, Kericho High School Principal Daniel Chelule said Sankok called the school on Wednesday last week and told them that his son would not be reporting as scheduled and requested more time.
The legislator is a former student at the school located on the outskirts of Kericho town.
"After the student failed to report to the school on Tuesday last week, his father called on Wednesday to inform us his son wasn't keen on reporting back to the school.
"He requested a week to resolve the issue. It's unfortunate that the matter would end on a sad note," said Dr Chelule.
Sankok's family recounted their final moments with Memusi.
Rosemary Sankok, the MP’s first child, said she had accompanied their father to their hotel to supervise the installation of CCTV cameras. They left her brother in the house.
The hotel is about 100 meters from the home.
Rosemary said her other sibling returned to the house only to find Memusi lying in a pool of blood.
She said the younger sibling never heard any gunshot.
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Police have recorded statements from employees at the home and family members, including the MP.
"Our officers are talking to employees of the hotel where the legislator was by the time of the incident.
"We are doing our best to find out the facts about the boy's death," said Ethaiba, the Narok County DCI boss.
Meanwhile, a somber mood engulfed Sankok's home as family members, friends and the legislator's colleagues trooped the home to condole with the family.