Durban - A 15-year-old girl and four of her friends have been arrested for the murder of the young woman's mother and step-father, Free State police said on Thursday.

According to provincial police spokesperson brigadier Motantsi Sam Makhele, the bodies of the murdered couple were found near Lovedale Plot in Maokeng.

The "elderly couple" had been stabbed, said Makhele.

"A joint venture with various police units was launched and intensified investigations led to the deceased’s house in Constantiapark, where blood stains were found," he said.

The teenage daughter and three of her friends, aged between 15 and 29, were arrested.