Tensions soared in the Serb-run part of Bosnia after police on Tuesday detained the man whose quest for truth in the death of his son has sparked months of anti-government protests.

Bosnian Serb police said they detained Davor Dragicevic after he failed to appear for questioning. Dragicevic's lawyers said he was hurt during the arrest, which police denied.

Several other people also were detained, including Dragicevic's ex-wife and some opposition politicians. Videos from the central square in Banja Luka, the main city in the Serb mini-state in Bosnia, showed police scuffling with citizens while making arrests. Police said an officer was injured.

Davor Dragicevic's "Justice for David" movement has demanded information about the March death of his 21-year-old son David. Police initially said it was a suicide, but the young man's family insists he was killed by someone else.

Davor Dragicevic has accused top police officials of covering up his son's slaying and protecting the killers, which authorities deny. His movement's demonstrations have drawn thousands of people and inspired citizens to also protest official corruption and the bleak economic prospects in Bosnia.

After the arrests, special police were deployed to the Banja Luka square and authorities removed a memorial for David Dragicevic. Bosnians have lit candles and laid flowers around photographs of him in the square for months.

Dozens of people gathered at the scene, some crying and shouting "Justice for David." They later started setting up a new, heart-shaped memorial amid occasional scuffles with the police officers securing the square.

The European Union delegation in Bosnia said it was "deeply concerned" about the arrests and demanded an explanation from Bosnian Serb police.

"We are following the developments closely in Banja Luka and urge everyone to stay calm and refrain from violence," the EU delegation and the EU Special Representative said. "Today's turn of events in Banja Luka sends a negative and alarming signal about the state of rule of law."

Local media reported that police wanted to question Dragicevic for allegedly "endangering security" with a protest this month during the election in parliament of a new Bosnian Serb government.

The Bosnian Serb government is dominated by the ruling coalition of pro-Russian nationalist leader Milorad Dodik. The opposition Party of Democratic Progress issued a statement accusing the government of "unseen repression" and demanded Dragicevic's release.

Bosnia remains tense and ethnically divided following the 1992-95 war that killed over 100,000 people and left millions homeless. The country consists of a Bosnian Serb and a Muslim-Croat entity.