Corey Johnson’s longtime best friend testified against him at his murder trial Thursday. Prosecutors say Johnson fatally stabbed a 13-year-old boy and tried to kill two other people during a March 2018 sleepover at a Palm Beach Gardens home. Johnson has entered a plea of not guilty by reason of insanity, with his lawyers saying depression medication and video games twisted his brain. Kyle Bancroft said he slept through most of the attacks and couldn’t tell if he was dreaming when he saw the bloody body of Jovanni Sierra on the second floor of his home. The trial resumes today.