A court statement said two of the suspects accepted their guilt in the assault after being charged in the preliminary hearing, though the men’s condition raised questions about whether they were speaking freely.

There had been earlier conflicting reports in Russian media outlets that said three or all four men admitted culpability.

Moscow’s Basmanny District Court formally charged Dalerdzhon Mirzoyev, 32; Saidakrami Rachabalizoda, 30; Shamsidin Fariduni, 25; and Mukhammadsobir Faizov, 19, with committing a group terrorist attack resulting in the death of others. The offense carries a maximum sentence of life imprisonment.

The court ordered that the men, all of whom are citizens of Tajikistan, be held in pre-trial custody until May 22.