Polish prosecutors have charged a Tunisian man with murder over a knife attack that sparked a riot in the north-eastern town of Elk.
Sunday's riot involved dozens of locals enraged by the killing of a 21-year-old Polish man, identified only as Daniel R, outside a kebab restaurant.
Investigators believe the Tunisian cook, 26, confronted Daniel R after he and another Pole stole two bottles of drink from the premises on Saturday.
Police detained 28 during the unrest.
Early on Sunday angry local Poles smashed some of Prince Kebab's windows and at least one firecracker was thrown at the restaurant. Anti-foreigner slogans were chanted, the Associated Press reports.
When police formed a cordon outside there were scuffles, as some rioters threw bottles and stones, and police resorted to using tear gas, Polish media reported.
The reports say the Tunisian has admitted taking a knife from the restaurant before running out after the two men.
Autopsy results are still awaited to determine the exact cause of death of Daniel R.
Polish TVN24 news says the Algerian owner of the restaurant ran out with the Tunisian cook during the quarrel on Saturday night.