Warrant Officer Sikheto Albert Nkuna, 46, had been accused of murdering his wife Leah in their Mamelodi West home on October 17, 2012.
The nursery school teacher was shot in the forehead. They still shared the house although they had been estranged for four years and lived separate lives. Nkuna denied shooting his wife.
The evidence of police ballistics expert Captain Chris Mangena was pivotal in Nkuna’s acquittal. Mangena was one of the witnesses for the State in the murder trial of paralympian Oscar Pistorius.
In a report, Mangena said in his view Leah Nkuna had probably been sitting in the bath and her wounds were most likely self-inflicted, although the possibility of someone else inflicting them could not be ruled out.
Judge Nico Coetzee said Mangena had been attached to the police’s forensics laboratory since 1995, examined more than 5600 cases and completed a host of courses in his field. His opinion could barely be faulted, he added.
Mangena was adamant the crime scene had been tampered with and the murder weapon and cartridge case removed from the scene.
This was not significant enough to prove Nkuna’s guilt, Coetzee ruled.
The State alleged Nkuna murdered his wife as only the two of them had been home at the time, there was no sign of a break-in and Nkuna had gun residue on his right hand.
A witness told the court Leah Nkuna had insulted her husband in front of others by making demeaning remarks about his inability to have an erection. Nkuna was aware his wife had an affair with another policeman at the Mamelodi West police station.
Four witnesses testified that Nkuna was unhappy because his wife had brought her boyfriend to a family tombstone unveiling. They alleged he had threatened to kill her several times. Nkuna denied this.
Coetzee rejected the evidence that Nkuna’s wife had insulted him. He rejected the evidence of the four witnesses about Nkuna’s alleged threats to kill his wife, saying they contradicted each other.
Nkuna however came across as a confident witness who never contradicted himself. His version that he found his wife’s body in the bath after going to wash his hands early in the morning was reasonably possibly true, Coetzee found.
The State had conceded he could have picked up the residue from a car seat, his wife’s body, or by shaking hands with another person.
Firearms, ammunition and gun residue were everywhere in his work environment, Coetzee added.
Nkuna was fired after his arrest. His advocate, JP Swanepoel, indicated he intended taking legal steps to seek his reinstatement.