Colombian authorities said that Thursday’s car bombing against a police academy that left 21 dead was carried out by a member of the country’s last remaining rebel group.

Defense Minister Guillermo Botero said in a press conference that the man who carried out the brazen attack, Jose Aldemar Rojas, was a member of the National Liberation Army and known by his alias Mocho Kiko.

He said Rojas was an explosives expert who had lost his arm manipulating explosives during his long career in the ELN rebel cell near the border with Venezuela.

Read more: AP