[3][4] The incident that triggered the riot was the killing of a Polish pedestrian struck, along with his companion, in a hit-and-run by a Romani male driver.

[1] The immediate cause of the riot was a hit-and-run accident just before midnight on 23 June 1991 on the pedestrian crossing at Piłsudskiego and Zuzanny Morawskiej streets.

[1] A speeding luxury car driven by seventeen-year-old Roman Packowski (who was of Romani ethnicity) hit and seriously injured two young pedestrians, killing one of them.

[7] Two days later, some sixty Mława youths targeted and destroyed the house of a local Roma leader.

[11] The eruption of ethnic violence at Mława in 1991 has been described as 'the renewal of anti-Gypsy racism in Poland' and is linked to a significant rise in Polish Roma asylum applications in the United Kingdom[12] and Sweden.

[13] However the fact the rioters selectively attacked only the wealthy Roma houses (called "belveders") supports the opinion that the riot was triggered by economic rather than nationalistic factors.