Editor and founder of the independent news website Interferencia, Herrero was convicted on charges of defaming a police colonel on May 22, 2023 after he wrote a story on him. The story was based on five anonymous sources and two reporting trips to southern Chile, according to Herrero. He was ordered to pay a fine and legal costs of the trial. Herrero co-authored La revuelta, a chronicle that recounts what happened in the streets of Chile in 2020.