Edson Isidoro/Izidoro Guimarães is a Brazilian nursing assistant and convicted serial killer. He confessed to five murders of which he was convicted of four, but is suspected of committing up to 131 in total. He claimed that he chose patients whose conditions were irreversible and who were in pain. Guimarães worked as a nurse in the Salgado Filho Hospital in the Méier district of Rio de Janeiro, Brazil. He was caught in 1999 when a hospital porter saw Guimarães fill a syringe with potassium chloride and inject a comatose patient who immediately died. The police were informed and a higher than average death rate on his ward increased their suspicions. On his arrest he confessed to five murders. He told a television reporter prior to his trial, "I don't regret what I did", adding "I did it to those in irreversible comas and whose families were suffering."