The attacks were caught on CCTV camera as shopkeeper Ashok Selvam and his staff were subjected to a series of blows and punches within one hour.
The three found guilty of the attacks at the Bristol magistrates court yesterday are twins Justin and Luke Lovedale, 17, and Nicholas Gardener, 17, who screamed racist abuse as they punched and kicked their victims.
The CCTV footage was shown to the court and all three were found guilty of racially aggravated assault in both shops.
In the first attack, the two twins - who were 16 at the time - punched and kicked a member of staff after they were refused vodka and cigarettes.
They pulled Selvam's T-shirt over his head and then rained blows on him.
District Judge David Parsons, who will pronounce their sentences on November 11, said: "Race hatred should be dealt with seriously by the court, and your victims deserve the protection of the court".
Published 24 October 2009, 10:30 IST