Eko Straza founder questioned over sonic cannon case

Bojan Simisic, founder of the environmental group Eko Straza, was stopped at a border crossing on his way back from a business trip and taken in for questioning in the case built around the sonic cannon at the protest of March 15, 2025 in Belgrade. The interview was conducted by inspectors of the Criminal Police Directorate, from the counterterrorism unit. He gave his statement as a citizen, was released as soon as it was taken, and his phone was not seized.

His organisation made the incident public in a statement on August 1. The case in which Simisic was questioned has nothing to do with any subject Eko Straza normally deals with. It rests on the claim that the use of a sonic cannon at the largest rally of last spring was staged in advance.

What Eko Straza said in its statement

The group said Simisic told the inspectors what he personally knew about that day, and pointed to who first raised the sonic cannon in public.

“Bojan gave a statement about his own knowledge of the event, including the fact that the first people to speak publicly and live on television about the use of the sonic cannon were Dragan J. Vucicevic and the lawyer Vladimir Djukanovic”

The record therefore now carries the name of Informer editor Dragan J. Vucicevic and that of lawyer Vladimir Djukanovic, along with the claim that both discussed the device live on Informer television. Police have said nothing about whether either man will be called in for a similar conversation.

How did the sonic cannon enter the investigation?

The Belgrade Higher Public Prosecutor’s Office said on June 19, 2026 that among documents seized during a search of the Faculty of Philosophy it had found minutes from a meeting held on January 22, 2025. Prosecutors argue those minutes describe steps that would simulate the use of a sonic cannon. The search itself took place on March 27, 2025, twelve days after the protest.

The date on the minutes is the heart of the dispute. The meeting was held almost two months before March 15, at a point when the rally prosecutors are talking about had not yet been called.

The students’ answer

The Students in Blockade replied that the document was written before the March 15 protest was even planned, and that it dealt with security risks at a rally at Autokomanda. They added that sonic cannons appear in that material among possible hazards, listed alongside water cannons and tear gas.

“If mentioning the possible use of force has become proof of guilt, then the problem is far bigger than a single set of minutes”

Prosecutors read the same passage as preparation rather than as a risk assessment. No court has ruled on which reading is correct, because no indictment over the sonic cannon has been filed.

Why this questioning differs from the earlier ones

Until now the case has revolved around student plenums and faculty paperwork. Simisic is not a student and was never part of those bodies, and Eko Straza is a group known for environmental campaigns and its own street actions. Questioning him widens the circle of people police are interviewing in this case beyond the universities.

The method differs too. No summons was sent to his address. He was stopped at the border as he entered the country, by a unit whose remit is counterterrorism. Eko Straza stressed that the interview was conducted with him in the capacity of a citizen rather than a suspect, and that no device of his was retained.

The protest of March 15, 2025 was the largest rally in the wave of student demonstrations, and it filled the stretch running along Kralja Milana Street, Terazije and Slavija. The contested moment from that day, when the crowd suddenly surged sideways, is still the subject of two irreconcilable claims a year and a half later: one side wants it established that a device was used, the other is running an inquiry against the people who say it was.

The next move belongs to the prosecutors. They have not said whom exactly the sonic cannon inquiry targets, nor whether Simisic’s statement will bring in the men he named.