Law enforcement reportedly detained a 16-year-old boy in Moscow on Friday on charges of making a bomb. The news agency TASS says police found an explosive device and other bomb components at the suspect’s home during a search.

Sources close to the investigation say the boy was in contact with the 17-year-old anarchist suicide bomber who killed himself and injured three officers in an attack on the FSB building in Arkhangelsk earlier in the week. The tabloid REN TV says the Moscow suspect is a fellow anarchist.

For more on the FSB attack The terrorist attack on a Federal Security Service branch in Arkhangelsk: what we know, so far