The identities of 13 more suspects have been determined, Poland’s police chief Jarosław Szymczyk was quoted as saying on Tuesday.
“Intensive work is being done with video material secured from surveillance cameras,” he added.
Around 800 people gathered for the city’s first-ever march supporting the LGBT community on Saturday, according to police statistics. Białystok authorities put the figure at 1,000.
Counterdemonstrators attempted to disrupt the event, with hundreds of them gathered along the entire route of the march. Cordoned off by the police, they tried to hinder the passage of the demonstrators several times. Some attacked the activists and chanted homophobic insults, according to reports.
Several hundred policemen from Białystok and other cities, aided by the Border Guard, provided security during the event. A helicopter hovered above the crowds and monitored adjacent streets and blocks.
Police spokesman Tomasz Krupa said that, apart from physical force, officers used flash-bang grenades and tear gas.