Three of the four suspects in the Moscow attack that left more than 130 dead plead guilty

With apparent signs of torture, three of the four suspects in the attack on a concert hall in Moscow pleaded guilty this Sunday.

The Basmanny District Court of Moscow formally charged Dalerdzhon Mirzoyev, 32 years old, Saidakrami Rachabalizoda, 30, Mukhammadsobir Faizov, 19, and Shamsidin Fariduni, 25, for committing a group terrorist attack that killed more than 130 people. The crime carries a life sentence.

The court ordered that the accused remain in preventive custody for two months, until May 22.

Of the four, Mirzoyev, Rachabalizoda and Fariduni, all from Tajikistan, admitted their guilt after being charged.

The fourth, Faizov, was brought to court in a wheelchair, apparently unconscious from a hospital. The alleged terrorist remained seated with his eyes closed throughout the entire process.

The defendant, seen with multiple cuts, was treated by doctors while in court, where he wore a hospital gown.

According to the Russian agency TASS, the court hearing took place behind closed doors and, according to the investigation, Faizov filmed the attack on the concert hall. As he had difficulty speaking, "the defense asked for a restriction measure, not connected with detention," TASS reported.

The other three had bruises on their faces, cuts on their body, and plastic bags around their necks, an object that presumably could have been used for suffocation torture.

One of the suspects, Rachabalizoda, had a heavily bandaged ear. He is presumed to be the terrorist whose ear was severed during interrogation, according to Russian media.

Russian media revealed reports of alleged torture. However, Western news agencies were unable to independently verify whether Russian security forces actually applied the methods in interrogations against the accused.

The hearing came as Russia marked a day of national mourning for Friday's attack on the Crocus City Hall concert hall outside Moscow. ISIS claimed responsibility for the attack.

According to Russian President Vladimir Putin, Russia captured the four suspected attackers on Saturday, in addition to seven more people who were detained on suspicion of involvement in the attack.

The Russian president also said that the attackers were captured while fleeing to Ukraine, a claim that Kiev strongly denied on Saturday.