Russian authorities have reportedly arrested another Tajik national in connection with the March 22 terrorist attack on the Crocus City Hall concert venue in Krasnogorsk that left more than 140 people dead and hundreds more injured.

Russia’s RBK news agency cited sources in law enforcement on April 26 as identifying the detained suspect as Jumakhon Qurbonov, 21, a native of Farkhor district in Khatlon province. .

Criminal proceedings have been instituted against him under the provisions of Article 205 (3) of Russia’s Penal Code -- committing a terrorist act that resulted in the intentional death of a person; an investigation is under way.  

Russian authorities have said 11 Tajik citizens and a Kyrgyzstan-born Russian citizen have been arrested in connection with the attack, Russia’s worst terrorist attack in two decades. Responsibility was claimed by the Islamic State-Khorasan (IS-K), an affiliate of the Islamic State (IS) terrorist group.

Russian investigators say the assault was carried out by four men, all Tajik nationals. Other detainees are being held for aiding and abetting the attackers.

Several Tajik suspects showed signs of abuse when they appeared in court in Moscow following the attack.  The four accused gunmen had bruised and swollen faces and showed other signs of having been severely beaten.  There were reports that one of them had his ear cut off during his arrest.

Some sources the Crocus attack was seen as a major failure for Russia's security and intelligence services.

The United States has said it gave specific information ahead of time, warning of a possible terrorist attack.  Iran reportedly also provided a tip ahead of time.