Mangual joined El Vocero newspaper during the 1970s. While he is not the only reporter who covers crime stories in that newspaper, his name is probably the most recognizable one out of crime reporters for El Vocero among Puerto Ricans. His trademark as a crime reporter has been the usage of Puerto Rican slang terms, such as Corrio como alma que lleva al Diablo (The person ran like a soul possesed by the Devil). This personal style has earned him awards, but also a lot of criticism among Puerto Rican readers.
De Jesus Mangual continues to write crime reports for El Vocero.