SARAJEVO (Reuters) - The mayor of the northwestern Bosnian town of Banja Luka has canceled Monday’s New Year celebrations for security reasons after protesters demanding the truth about a student’s death prevented a public concert taking place the previous evening.

The group “Justice for David” protested on Sunday for the 280th day in a row, demanding the resignations of the Bosnian Serb interior minister and other police officials who they believe covered up the alleged murder of David Dragicevic in March.

During Sunday’s march, which lasted several hours, demonstrators prevented a regional folk star from performing. Special police dispersed the crowd, detaining several people.

“There will be no concerts,” Mayor Igor Radojicic told a news conference. “Banja Luka will be mute at midnight for the first time since the war,” he said, referring to 1992-1995 Bosnian war.

“Those who need to resolve Dragicevic’s case should understand this silence,” Radojicic added, calling on the police and judicial authorities to solve the case and allow life in the town to return to normal.

Bosnian Serb leader Milorad Dodik, who is the chairman of Bosnia’s three-man inter-ethnic presidency said the protesters had “crossed all lines”, adding that he supported a police ban on unapproved protests.

Residents of Banja Luka were expected to gather in the central square later on Monday for concerts by regional pop stars and a fireworks display, as well as events for children.

Dragicevic’s father Davor has led a daily protest since his son’s body was found in a creek in the town after he was missing for six days. He believes David was murdered and that the police were involved in covering up the killing.

His quest has grown into a larger movement of citizens fed up with corruption and what they say is Bosnia’s poor rule of law. Smaller-scale protests in solidarity with the grieving father have taken place across ethnically divided Bosnia but also in neighboring Croatia and Serbia.

Police initially said David Dragicevic had committed suicide but later said there was a possibility he had been killed. The prosecution team handling the case have not presented any evidence of murder.

Bosnian Serb interior minister Dragan Lukac has previously said that the police carried out their investigation professionally.

The police detained Davor Dragicevic last week over alleged threats to Lukac, later releasing him.

On Monday, police issued a warrant for his arrest, along with several other protesters who they said caused incidents on Sunday.