Russian investigators have confirmed and are formalizing the connection of the perpetrators of the terrorist attack in the Crocus City Hall near Moscow with Ukrainian nationalists, Russian Security Council Secretary Nikolay Patrushev said on Tuesday.
"During the investigation, the connection of the direct perpetrators of this terrorist attack with Ukrainian nationalists has been confirmed and is being formalized," Patrushev said in Russia's Arkhangelsk at a security meeting.
He also pledged that all those involved in the deadly attack would be punished.
"Perpetrators, accomplices and masterminds of this monstrous, bloody terrorist attack and other affiliated persons, wherever they hide and no matter how they try to cover up the traces of the crime, will face the punishment they deserve," Patrushev said.
On March 22, several armed men broke into Crocus City Hall and started shooting indiscriminately at concert-goers. They also started a fire in one of the auditoriums, which was full of people ahead of a concert.
The attack left 145 people dead and many more injured. The four main suspects in the case tried to flee the scene in a car but were detained and charged with terrorism. Russian authorities believe their plan was to flee to Ukraine, where the masterminds of the attack had arranged a safe haven for them. An investigation is underway.