The assault took place on March 22, 2024, at Crocus City Hall, where gunmen opened fire on concertgoers waiting for a performance before setting the building on fire.
Authorities say the attack killed 149 people and wounded more than 600, making it one of the deadliest attacks in the Russian capital in years.
A faction of the Islamic State claimed responsibility for the massacre.
According to investigators, four gunmen from Tajikistan carried out the attack, while others helped with logistics, including providing a car and accommodation.
The court handed life sentences to fifteen of the defendants. One person received a 22-and-a-half-year prison term, while three others were sentenced to nearly 20 years.
The trial began in August 2025 in a military court and was held behind closed doors due to security concerns.
Russian officials, including President Vladimir Putin, have suggested that Ukraine was involved in the attack, an allegation strongly denied by Kyiv.
Investigators say the four main suspects were arrested just hours after the attack as they attempted to flee.
