A 29-year-old Uzbek citizen has been detained for allegedly planting the bomb that killed senior Russian general and his assistant, the Russian Investigative Committee said Wednesday.

Lt. Gen. Igor Kirillov, who headed Russia’s radiological, biological and chemical protection forces, was killed by a remotely detonated bomb planted in an electric scooter outside an apartment building some 7 kilometers (4 miles) southeast of the Kremlin.

The Uzbek suspect was allegedly recruited by Ukraine’s special services and arrived in Moscow under their instruction, the committee said on its official Telegram channel.

“The detainee received a homemade explosive device and placed it on an electric scooter which he parked at the entrance to the residential building where Igor Kirillov lived,” according to the committee’s statement.

To monitor Kirillov’s residence, the suspect rented a car and equipped it with a surveillance camera, the committee added.

“The footage from this camera was broadcast online to the organizers of the terrorist attack in the city of Dnipro. After a video signal was received about the soldiers leaving the entrance, the explosive device was remotely activated by them,” the committee said, adding that “other persons involved in organizing this crime are being identified.”

The detained Uzbek citizen was guaranteed a monetary reward of $100,000 and residence in an unspecified European country, according to the committee.

Russian officials have responded furiously to the general’s death, vowing punishment “without a doubt and without mercy.”