Tajik national Dzhumokhon Kurbonov is accused of providing the attackers with communications and funding.
The judge of the Basman District Court of Moscow decided that D. Kurbonov will be held in custody until May 22, while the investigation is conducted and the trial begins.
Russian state news agency RIA Novosti reported that Kurbonov was detained for 15 days on April 11 on an administrative charge of minor hooliganism.
Mediazona, an independent Russian media outlet, noted that it is common practice for Russian security services to hold a person in custody pending a criminal case against them.
According to RIA Novosti, twelve defendants have already been arrested in this case, including the four who allegedly carried out the attack at the Crocus City Hall concert hall.
In late March, the four men were brought before the same Moscow court on terrorism charges and bore signs of brutal beatings. One of them seemed barely conscious during the court hearing.
The court then ordered that the men, who have all been identified in the media as Tajik nationals, must also be held in custody until May 22.
The Islamic State (IS) extremist group has repeatedly claimed responsibility for the massacre, in which gunmen shot people waiting for a performance by a popular rock band and then set fire to a building.
But Russian officials, including President Vladimir Putin, have insisted without providing evidence that Ukraine and the West were involved in the attack.
Ukraine denies any involvement, and its officials claim Moscow is using the allegation as a pretext to intensify fighting in Ukraine.
Tags: Russia arrested suspect concert hall attack killed people
