A 15-year-old boy has been found guilty of murdering a shopper who was knifed to death after challenging him for messing around in a supermarket’s toilets.

Jurors convicted the youngster of the killing after hearing how 53-year-old Ian Kirwan was knifed in the heart by the youth – then aged 14 – acting as a part of a masked gang which “terrorised” members of the public in Redditch.

The killer, from Birmingham, travelled with four other boys by train to the Worcestershire town on March 8, last year, where Mr Kirwan was subjected to a minute-long attack near the entrance of an Asda store.

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Jurors cleared three of those other youths – two aged 14 and one aged 16 – of murder and manslaughter but 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.

A ten-week trial at Birmingham Crown Court, was told Mr Kirwan, an artificial intelligence engineer who worked at Jaguar Land Rover’s Coventry headquarters, was an “unfortunate member of the public in the wrong place at the wrong time”.

All those convicted will be sentenced, at the same court, on February 15.