What do we know about the suspects in the Russian concert shooting?

By Filipp Lebedev

(Reuters) -Four suspected gunmen have been arrested and placed in pre-trial detention over Friday's attack at the Crocus City concert hall near Moscow that killed at least 137 people.

All have been identified by Russian media as citizens of Tajikistan. All bore visible injuries when they appeared at a Moscow court on Sunday. The Kremlin declined to comment on Monday when asked if they had been tortured.

MUHAMMADSOBIR FAYZOV

Fayzov, 19, is the youngest of the detainees. Russian media said he had been working as a barber in a town northeast of Moscow.

On Saturday, several Telegram channels published a video showing him being questioned while lying on a hospital bed. Photographs circulating online on Sunday appeared to show Fayzov with one of his eyes missing. He was taken to court in a wheelchair and the hearing was closed to journalists, unlike those for the other three suspects. He was photographed sitting in the wheelchair with his head slumped backwards and both eyes closed, apparently oblivious to what was going on around him.

DALERDZHON MIRZOYEV

Mirzoyev is 32 and has four children.

In a video of his interrogation, he said through an interpreter that he lived "in a hostel near the motorway" with another man, Mukhamad, and that 10-12 days earlier they had bought a car "for work" from someone called Abdullo. He was not seen speaking about the attack.

Mirzoyev occasionally flew from Moscow to Tajikistan and back, according to leaked air travel data. In 2011 he was prosecuted for violating immigration rules, according to a court database.

Photographs from the courtroom showed him with cuts and heavy bruising to his face.

SHAMSIDIN FARIDUNI

Fariduni, 25, said in an interrogation video published on social media that he had arrived from Turkey on March 4. He was trembling while being questioned by the side of a road, with his hands tied behind his back. He said that he had "shot people" in Crocus City Hall "for money", having been offered 500,000 roubles ($5,400) by a person he did not identify.

A photograph published later by Grey Zone, a Telegram channel that is close to the Wagner mercenary group, showed Fariduni lying on the floor with his trousers rolled down to his knees and someone standing on his legs.

When he appeared in court on Sunday, Fariduni had a large bruise on the left side of his face.

SAIDAKRAMI RACHABALIZODA

Rachabalizoda, 30, was shown being beaten and abused in a series of videos published by Grey Zone. In one clip, a man in camouflage uniform cuts off part of his right ear and stuffs it in the suspect's mouth. "You now have one ear left," says a voice in another video in which Rachabalizoda is being interrogated. On Sunday he appeared in court with a large bandage around his right ear and with bruises and caked blood on his face.

In 2018 Rachabalizoda was prosecuted and fined 2,500 roubles ($27) for a violation of immigration rules, according to a court database.

NOTE - Reuters was able to verify by analysis of the images that the men seen being interrogated in the pictures and videos were the same men who appeared in court on Sunday.

(Editing by Mark Trevelyan and Alex Richardson)