Gunmen killed a former top government security adviser in Guatemala early Tuesday, a week after he was fired by President Alvaro Colom amid complaints he had become too powerful.

Victor Rivera was shot dead while driving through Guatemala City, Interior Ministry spokesman Ricardo Gatica said. His assistant was wounded.

A Venezuelan citizen, Rivera was hired by the government in the 1990s to help authorities confront a wave of kidnappings. His negotiating skills won the release of dozens of captives and the admiration of Guatemala’s business elite.

But President Alvaro Colom dismissed him last week, saying he had become too powerful and his investigative team was “too independent.”

Human rights officials allege that police under Rivera’s direction were killing suspected gang members, although he denied any wrongdoing.