Russian authorities detained an Uzbekistan national on suspicion of killing a top general in a Moscow bomb attack, and said he’d been recruited by Ukrainian security services to carry out the assassination.

The detainee was promised $100,000 and safe passage to a European country if he helped plant the explosive device that killed Lt. Gen. Igor Kirillov, the head of Russia’s radiological, chemical and biological defense forces, the Investigative Committee in Moscow said in a statement Wednesday on Telegram.

Kirillov and his assistant were killed when the bomb planted on a scooter detonated near the entrance to an apartment building in Moscow on Tuesday. He is the most senior Russian commander to be assassinated deep inside Russia since the Kremlin began its February 2022 invasion of Ukraine.