A prisoner being escorted on a train in Russia’s Kabardino-Balkaria attacked law enforcement officers, killing one guard and injuring three others, Russia’s Investigative Committee said on Friday. 

Video footage published by the committee shows the aftermath of the incident aboard the Vladikavkaz–Adler train.

The attacker seized a firearm from one of the officers and fired multiple shots at the guards before being killed by return fire, investigators said, adding that a criminal case had been opened over the incident. 

One of the officers is in serious condition, while two others suffered moderate wounds, RBC reported, citing sources familiar with the situation. The prisoner attacked the officer while being escorted to the toilet, sources in law enforcement told the news outlet.

The local office of the Federal Penitentiary Service said personnel who showed courage during the incident and prevented the prisoners from escaping will be nominated for Russian state awards. One of them will be nominated posthumously.

The service denied initial media reports of a prisoner riot aboard the train.