As civil unrest becomes more violent in Ukraine, the interim authorities should ensure that they comply with Ukraine’s international human rights obligations to protect the right to life. The shocking events of May 2, 2014 in Odessa, which left at least 46 people dead and 200 injured, should be thoroughly and impartially investigated.

A football match was to take place at 5 p.m. on that day between the Kharkiv Metallist and the Odessa Chernomorets teams. Violent clashes broke out at about 3 p.m. in the city center between supporters of the interim authorities in Kiev and protesters opposing the Kiev authorities, and spread to other parts of the city.

According to information obtained from videos viewed by Amnesty International and Human Rights Watch and interviews with witnesses by Human Rights Watch, the opposing groups fought each other with wooden batons, Molotov cocktails, chunks of asphalt, and similar weapons. After a government supporter was shot dead, the pro-Kiev crowd charged a camp of anti-Kiev protesters that had been located outside the trade union building for several months.

Anti-Kiev protesters and people who had been involved in the clashes sought cover in the trade union building when pro-government crowds attacked them, witnesses said. The building subsequently caught fire, trapping many people in the flames. Many died from burns, smoke inhalation, or as a result of jumping from the building, but there were also some who died from gunshot wounds.

The circumstances of their deaths and the nature of their injuries gives rise to many questions. Only a thorough and impartial investigation will provide adequate answers. The investigation should aim to identify the causes of the fire in the trade union building and the circumstances in which the victims met their deaths.

The investigation should also examine why the policing that day was so inadequate, in particular why the police were apparently so unprepared for the confrontation, and assess the extent to which it could have been foreseen given the substantial support for Kiev among football fans and the fact that anti-Kiev forces had been assembled for weeks in the city, and why they failed to take effective steps to contain the violence once it broke out.

According to some media reports, police failed to take action to prevent the violence, and video footage available on the Internet shows police officers apparently standing by while preparations are made by members of both groups for acts of violence. Indications that some of those who took part came prepared for violence are provided by video footage which shows people removing wooden batons, Molotov cocktails and other weapons from cars.

There is also video footage of police standing by while violence is taking place, including handguns being fired, stone-throwing, and beatings by people on both sides. Witnesses also told Human Rights Watch that they saw situations in which police officers did not intervene even when violence was taking place in front of their eyes. One witness told Human Rights Watch, “The police just stood there, they saw people fighting violently but said that they won't intervene until they receive an order to do so.”

International human rights and law enforcement standards underline that police have a responsibility to maintain public safety and protect all persons against illegal acts, and must maintain and uphold the human rights of all persons. In particular, police play a vital role in the protection of the right to life, liberty, and security of the person. In carrying out their duties, police must as far as possible use nonviolent measures before resorting to any use of force, which they may use only when strictly necessary and proportionate to the specific law enforcement purpose. In the context of the events which took place in Odessa on May 2, it is not clear why the police failed to take adequate action, in compliance with these obligations, to prevent the serious injuries and loss of life.

In addition, the authorities should urgently conduct a thorough investigation into the policing of the events, review procedures, and ensure that police officers are properly trained and equipped to carry out their duties in such challenging circumstances, in a manner that conforms with international human rights law and standards.

Following the events of May 2, over 100 people were detained on suspicion of taking part in the violence. The authorities released 67 detainees on May 4, after protesters threatened to storm the pretrial detention facility in Odessa. There were reports that those released are opponents of the Kiev government. Other concerns have been raised that only those who were opponents of the Kiev government were detained in the first place. The authorities should respond to these concerns. Those who remain in detention should be informed promptly of the reasons for their detention and charges against them, be able to communicate with their families and have access to legal counsel of their own choosing, and be brought promptly before a judge who should rule on the lawfulness of their detention.

In reaction to the events of May 2, on May 4 Acting Prime Minister Arseniy Yatseniuk blamed police officers for the failure to prevent casualties and fired the Odessa police chief and deputy chief. Yatseniuk also announced that a special investigative group had been set up by the general prosecutor’s office to investigate the events. On May 6 the minister of internal affairs announced on his Facebook page that international experts would be invited to join the group. The newly appointed police chief said in a statement to the media that a team of Kiev investigators was working on establishing what had happened and that they would soon be joined by independent experts from Israel and Europe.

It is essential that whatever precise form the investigations take, they are truly effective and independent and carried out by individuals of recognized competence, integrity, and independence. This is essential in order to ensure that they are effective in ascertaining the truth of what happened on May 2and that they gain the trust of all parties in Ukraine.

The authorities should keep the United Nations Office of the High Commissioner for Human Rights (OHCHR) and the Organization for Security and Cooperation in Europe (OSCE) informed of the progress of the investigations, and when the investigations are completed the results should be made public as soon as possible.