The brother of a Dullstroom man who allegedly shot dead his wife last year on Monday claimed police had "tampered" with evidence in the case.

Cornelis Riekert testified in the trial of his brother, Johan (43), who has denied guilt to a charge of murdering his wife, Riekie, at a trout shop in Dullstroom in March last year.

The accused's brother testified that he and his mother went looking for Johan after being phoned by police and receiving a text message saying "Riekie shot me. I grabbed the pistol and shot back".

He later found his brother on a gravel road about 20 km from their farm after Johan phoned his mother. The two of them took his brother to hospital and informed police of his whereabouts.

The witness, a former policeman, was adamant that his brother was injured and that his shirt was soaked in blood.

The steering wheel and gear shift of his car was also full of blood and there was a tennis ball-sized blood smear on the driver's seat.

He said police did not investigate his brother's car for blood, and that evidence that no trace of blood could be found could not be correct.

No trace of evidence

He insisted there were no longer any traces of blood in the car when he received it back from police several days later.

He concluded that police must have tampered with the evidence, but could not supply any reason why this would have been done.

A blood stain only emerged on the seat much later and tests performed on the seat almost a year later proved that there had been blood in the car, he added.

Riekert earlier testified that he could only remember seeing a red dot and then everything going black before he found himself standing over his wife's body with a firearm pointed at her.

He claimed his wife became aggressive "when she had her period" and had threatened him with a firearm because of his suspected affair with another woman.

He said he had gone to the shop that day to discuss her plans to divorce him and insisted he had only agreed to a divorce because he thought she would come to her senses once she had stopped menstruating.

He claimed he was about to put his firearm back into his pocket when she suddenly made a grab for it, a struggled ensued.

Final arguments will be presented in the case on Tuesday.

Sapa