Austin Harrouff, 25, has pleaded not guilty by reason of insanity to two counts of first-degree murder and other charges for his August 2016 slayings of John Stevens, a 59-year-old landscaper, and his 53-year-old wife, Michelle Mishcon Stevens. The former Florida State University student has waived a jury trial, meaning Circuit Judge Sherwood Bauer will decide whether Harrouff was insane when he killed the couple, and seriously injured the neighbor who came to their aid.