The true mastermind behind the shooting in Moscow remains under investigation, with factors including potential ISIS-K involvement and allegations against the Kiev regime being scrutinized.

The terrorist attack on Crocus City Hall outside of Moscow on March 22 claimed the lives of at least 143 people, and more deaths are certain.

Alexander Bortnikov, the director of Russia’s Federal Security Service (FSB), announced on Friday that 11 suspects, including the four alleged participants directly involved in the terrorist attack on the Crocus City Hall concert venue, had been arrested.

According to The New York Times, U.S. officials revealed that U.S. Intelligence knew that ISIS-K was planning a terror attack on Moscow.

According to Bortnikov, the suspects were held in the Bryansk region, which borders Ukraine.

Andrey Popov, a reserve FSB colonel and member of the Association of Veterans of the Alfa anti-terror squad, stated in an interview with that the fact that the suspected terrorists intended to cross the Russian-Ukrainian border indicates that they planned their evacuation routes via Ukraine.

“It would be unrealistic for the terrorists to cross the Ukrainian border without contacts with the country’s special services or the Ukrainian side on the whole,” Popov said.

“In other words, the version about ISIS’* involvement in the Crocus City Hall attack – claimed by the US-led West – holds no water. All these citizens with Tajik passports were moving towards Ukraine, which indicates that it was the Kiev regime who ordered this atrocity,” the reserve FSP colonel added, referring to the attack.

The US “definitely” could finance this murderous shooting spree, he added, and Washington could “directly or indirectly” orchestrate it since “terrorism in the form of Ukraine has no other sources of funding except from the US and the UK.”

In this line, he noted that the Russian President, Vladimir Putin, sent his sympathies to the US following the 9/11 terrorist assault, but the US had not done the same in relation to the Crocus City Hall attack.

Popov also praised the work of the FSB, suggesting that the Federal Secret Service was keeping an eagle eye on the terrorists from the crime scene from the Crocus City Hall in order to find out more information about the accomplices, the means of communication, and their direction of travel. “So after the FSB obtained the information in full volume, a decision was taken to detain the terrorists,” Popov went on, recalling that they were taken alive.

With 143 confirmed dead in the Crocus City Hall attack, the Russian Investigative Committee has issued a warning that the death toll from the carnage could grow much more.