The Russian Investigative Committee said Friday that it had found evidence showing that the terrorists involved in the Moscow concert hall attack were planning to cross into Ukraine to receive their reward.

"On the instructions of a coordinator, after committing the crime, the terrorists drove in a car towards the Russian-Ukrainian border to subsequently cross it and arrive in Kiev to receive a reward they were promised," the committee said on their Telegram.

It added that a man, who introduced himself using a pseudonym, helped coordinate the terrorists' actions at both the preparation stage and after they attacked the concert venue. He did this through audio messages sent on Telegram.

The committee also said a ninth suspect linked to the attack had been detained Friday.