A Special Agent in the U.S. Secret Service agent testified Thursday in the punishment trial of a former East Texas nurse convicted of killing four men by injecting air into their arterial systems. The agent testified that he searched William George Davis’ computer and found that he had viewed an online article titled, “List of serial killers by the number of victims,” about a month before his arrest in 2018. Davis faces life in prison without parole or death by lethal injection.