Kariuki was a safari guide and was secretly a poacher. He had short black hair, dark brown eyes, and donned a striped dark fern green shirt underneath a cream vest with a name tag and carried a pair of binoculars at the time of his death.
Kariuki was found on the savanna covered in elephant footprints and with an arrow shot into him. According to Angela, despite the elephant footprints, the arrow found on him was the murder weapon. The arrow was poisoned by the tree Acokanthera schimperi. The poison itself would have been enough to cause a cardiac arrest in the victim. She managed to determine that the killer had to be knowledgeable in plants in order to construct the poison.
Relationship with suspects
Kariuki was the safari guide showing diamond heiress Lavinia De Brills around. Kariuki was cheating on his wife, Damaris Maina, with wildlife protection ranger Nyota Adhiambo before Nyota broke it off after she had found out that he was married. Kariuki was also running a secret poaching operation with Muthui Ndiritu, where the latter hunted elephants while Kariuki found buyers for the ivory tusks. When Muthui asked for an equal split of the profit, Kariuki angrily threw a rock at him, insisting that he deserved more as he was the one finding buyers. Kariuki was also bribing bureaucrat Melvin Cheruiyot (who had issued Kariuki his safari guide permit) to turn a blind eye to the poaching operation.
Killer and motives
The killer turned out to be Nyota.
After denying involvement, Nyota admitted she killed Kariuki. Because she loved the victim, she told him everything she knew about elephants while they were dating. Later on, she discovered that he used the knowledge to run his poaching operation. Feeling betrayed, Nyota shot Kariuki with a poisoned arrow. Judge Adaku sentenced her to 10 years in prison.