A Russian intelligence agency said Wednesday that it has detained a suspect for the killing of a senior general in Moscow.

The suspect was described as an Uzbek citizen recruited by Ukrainian intelligence services.

Russia’s Federal Security Service, or FSB, didn't name the suspect but said he was born in 1995. According to a statement by the FSB, the suspect said himself that he was recruited by Ukrainian special services.

Lieutenant General Igor Kirillov was killed Tuesday by a bomb hidden in a scooter outside his apartment building in Moscow, a day after Ukraine’s security service levelled criminal charges against him. A Ukrainian official said the service carried out the attack.

Kirillov was the chief of the military’s nuclear, biological and chemical protection forces. His assistant also died in the attack.