After a fine from UEFA for crowd trouble at their opening Euro 2012 match with Ireland, and amid a probe over racism during their game with Italy, Croatia could be back in the dock after fans hurled a flare in their final group fixture with Spain.
Adding to the danger, the flare was thrown by fans in an upper stand onto fellow Croatia supporters down below, forcing the latter to scramble clear.
Stewards in the Gdansk Arena rushed to remove the burning device from the crowd, as smoke curled over the Croatian net, with German referee Wolfgang Stark calling a brief halt to the match.
Despite the announcer's appeals to fans to behave, Croatia supporters lit two further flares just five minutes into the second half, but Stark waved play on despite the smoke over the Spanish goal.
Another was set alight 10 minutes from the final whistle, after a Croatian attack in what was to be a 1-0 defeat by Spain.
On Friday, Croatia were fined 25,000 euros ($31,400, 20,000 pounds) because their fans had lit flares and let off smoke bombs to celebrate goals in the 3-1 win in the Polish city of Poznan the previous Sunday.
A spectator also got on the pitch and missiles were thrown at the Group C game.
On Tuesday, UEFA is due to announce its ruling over flares and fireworks, as well as racist abuse of Italian forward Mario Balotelli, who is black, during Croatia's 1-1 draw with Italy last Thursday.