Lawrence Warunge, who confessed to killing his family told investigators that he was inspired by a TV show.
The 23-year-old Mt Kenya university IT student told police he was inspired by Villanelle character in the TV series dubbed 'Killing Eve'.
Police said they arrested Warunge after he went missing since Tuesday when his parents, two brothers and a worker were brutally murdered at their home in Kiambaa Constituency, Kiambu county.
After he was arrested, he later confessed to the incident and led police to a residence in Mai Mahiu area on Saturday where they recovered the killer weapon- a kitchen knife-, clothes, shoes and a piece of paper.
Lawrence had thrown the exhibits to a pit latrine but detectives dug the wall of the latrine and used ropes to recover the exhibits from the 20-feet deep pit.
He later took the detectives to an open field in the same area where he said he burnt some of the evidence.