A 15-year-old has been convicted of murdering software engineer Ian Kirwan, who was stabbed in the chest after a row at an Asda in Redditch.
Three other youths – two aged 14 and one aged 16 – were cleared of murder and manslaughter but jurors found them guilty of violent disorder.
A fifth boy, aged 16, was acquitted of murder, manslaughter and violent disorder, having claimed he was not involved in the fatal confrontation and could not have predicted it.
Mr Kirwan, 53, died after the incident in the car park of the supermarket in Worcestershire on 8 March last year.