A farmer was murdered and his wife assaulted by five people who pretended to buy sheep from their farm near Wolmaransstad in the North West, police said on Monday.Colonel Adele Myburgh said three men and two women visited the farm at around 17:30 on Sunday."The farmer sells sheep directly to the public and they pretended that they wanted to buy. The farmer and his wife went to the kraal. The people were picking out the sheep they want, catching the sheep and tying them," she said.The group then suddenly overpowered the farmer, 67, and his 66-year-old wife.The women took the wife to the farmhouse and demanded the safe keys, which she gave to them. The armed group assaulted both of them.Myburgh said that during the ordeal, the couple's son, 43, came from another kraal and saw people running in different directions."He came upon the body of the farmer in the sheep kraal. He had allegedly been stabbed with a sharp instrument and also tied up."The son called for help and his mother was admitted to hospital.Myburgh told News24 that no one had been arrested.