A sex attacker murdered a man who confronted him over the rape of a schoolgirl.

Kenneth Wheeler stabbed Scott Mackenzie to death and wounded the victim's son in a knife attack at his home in Shotts, North Lanarkshire.

Delivery driver Mr Mackenzie, 41, had been enjoying a summer evening with family and friends after a barbecue when he was told of the sex attack on the teenager.

He went to neighbour Wheeler's home where the fatal assault took place.

The 33-year-old murderer then went to his victim's house and threatened to kill his wife Tracey, a teenage witness told the High Court in Edinburgh.

She said Wheeler was armed with a large kitchen knife, adding: "It was covered in blood. It was as though he was possessed. He just had an evil look on his face."

The incident ended when police officers arrived and used pepper spray to subdue Wheeler.

Wheeler was found guilty of raping the 14-year-old girl at his home in Inverkip Drive, Shotts, on June 5 after supplying her with alcoholic drinks.

He was also found guilty of murdering Mr Mackenzie and attempting to murder his son Jamie, 20, at his home on the same date.

Judge Lady Carmichael told Wheeler there was only one sentence she could impose for the crime of murder but she would also have to fix a minimum term he must serve before becoming eligible to apply for parole under a life sentence.

The judge deferred sentence on Wheeler until February 1 at the High Court in Glasgow for the preparation of a background report.