Cigarette butts found at a crime scene have been linked to one of the suspects charged with the murder of lawyer Willie Kimani, his client Josphat Mwenda and taxi driver Joseph Muiruri.
Dr Joseph Kagunda Kimani, an analyst from the Government Chemist, said five cigarette butts found at an open field in Mlolongo match the DNA profiles of Peter Ngugi Kamau, an alleged police informer.
Prosecutors suspect the three victims were executed in the open field on the night they were reported missing.
The three were killed in cold blood on June 23, 2016 after attending a court case in Mavoko.
Four police officers — Fredrick ole Leliman, Stephen Cheburet Morogo, Sylvia Wanjiku Wanjohi and Leonard Maina Mwangi — and Mr Kamau have denied killing the three.
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Dr Kimani confirmed to Justice Jessie Lesiit that the DNA profiles collected from the cigarette butts match those of Mr Kamau.
He said the DNA can only be that of Mr Kamau “unless he has an identical twin brother”.
The expert said he received close to 70 items, including water bottles, clothes, cigarette butts, juice cans and wooden sticks from the officer investigating the case.
He said he examined the items to check for the presence of biological evidence.
He explained to the trial judge that the filter on the butt of a cigarette is a good retainer of DNA, and hence it was easy to match swabs collected from Mr Kamau.
Dr Kimani said it is not easy to gather DNA from an open surface, especially if the surface has been exposed to moisture and sun rays.
Dr Kimani further told the court that a bottle containing partially consumed mango juice contained Mr Mwenda’s DNA.
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The bodies of Mr Kimani, a human rights advocate, Mr Mwenda and Mr Muiruri were recovered from the river, near Donyo Sabuk, one week after they were reported missing.
Mr Kimani, who worked with the International Justice Mission, had gone to court to represent Mr Mwenda in a case the latter had filed against Mr Leliman in Movoko.
The lawyer and his client were kidnapped along with Mr Muiruri, a taxi driver hired by Mr Kimani, as they left the Mavoko Law Courts.
Earlier, Dr Kizzie Shako, a police pathologist, denied claims that Mr Kamau was crying the day he appeared before her for a mental check-up. Mr Kamau’s lawyer alleges that his client was tortured. The trial continues.