Javier Valdez was an award-winning journalist and Agence France-Presse contributor (File) Mexico City: A second man accused of murdering Mexican journalist Javier Valdez, an AFP contributor, was convicted on Tuesday, the prosecutor's office announced. Juan Francisco Picos Berrueta, known as "El Quillo," was found guilty as "a material co-perpetrator in the murder", the prosecution said in a statement. He will be sentenced at a later date and faces up to 50 years in prison as he refused to plead guilty in exchange for a shorter term. He was tried as the main perpetrator in Valdez' assassination. Valdez, who was a co-founder of the Riodoce weekly newspaper and a prominent chronicler of Mexico's deadly drug war, was shot dead four years ago in Culiacan, the capital of the northern Mexican state of Sinaloa.