BOGOTÁ, Colombia — The suspect in a car bombing that left 21 people dead on Thursday in Bogotá, the capital,was a member of the country’s largest remaining guerrilla group, the defense ministry said Friday.

José Aldemar Rojas Rodríguez, the assailant who was also killed in the attack, was a member of the National Liberation Army, a Marxist rebel group known as the ELN, said Guillermo Botero, the Colombian defense minister.

The group did not claim responsibility for the bombing, but it has stepped up attacks against the government since its rival, the Revolutionary Armed Forces of Colombia, or the FARC, signed a peace deal with the government in 2016.

Thursday’s attack was the first car bombing in Bogotá in years, a gruesome reminder of a time when drug lords and rebel groups ravaged the capital’s streets with car bombs, killing hundreds of civilians and members of the security forces. Since the signing of the peace accords, the Colombian government has said it turned the page on that violent era.