Adrian Gonzalez, who has been jailed for nine years now for the brutal sexual assault and murder of a girl who lived in the same Santa Cruz apartment complex as him, heads to trial this week to determine if he should remain incarcerated.Gonzalez was 15 years old in 2015 when he confessed to the murder of eight-year-old Madison "Maddy" Middleton. He was jailed for the crime, initially in a juvenile detention facility, but he never stood trial. Defense attorneys successfully argued that he could not be tried as an adult, which sent his case into legal limbo for years, until he ultimately pleaded guilty in 2021 and was officially convicted.Under California law, someone convicted of a crime as a juvenile would be eligible for release on their 25th birthday. However, because of the heinous nature of the murder, Santa Cruz County Superior Court Judge Denine Guy ruled in August that Gonzalez should stand trial so that a jury can decide whether he remains a threat to society, and whether he has been rehabilitated.Public Defender Athena Reis argued in a July hearing that Gonzalez is "simply not the same person he was nine years ago," and "He’s worked hard to become a healthy and safe person."But prosecutors have their doubts. Prosecutor Tara George argued in the hearing that Gonzalez has, perhaps, just learned how to "check all the boxes" in an "institutional setting" so that he'll be credited for good behavior.George further argued, "Nobody has seen a person like Adrian before. Nobody has seen a case like this before. Adrian went from zero to 100, and there is not one person who can say why."Defense attorneys have long contended that Gonzalez was a depressed teen who acted out impulsively. He admitted that he was planning to kill Middleton in order to get sexual gratification, and he planned to kill himself afterwards, so he believed he would not live long enough to face any punishment for the crime.He also admitted to strangling the girl for 30 minutes after luring her to his mother's apartment for ice cream, sexually assaulting her, and then when she showed signs of life and was moaning, stabbed her several times in the neck before attempting to dispose of her body in a recycling bin.Jury selection will begin in the trial on Tuesday, as Bay Area News Group reports.Gonzalez, who has remained in the juvenile justice system, has been incarcerated at a facility in Sonoma County since the state shut down the statewide juvenile justice division in 2023. Counties are now responsible for all juvenile offenders, and a contract for Gonzalez's incarceration was taken over by Sonoma County from Santa Cruz.The trial will confirm or deny a two-year extension for Gonzalez's incarceration, and it's not clear what happens after that two years is up.Previously: Convicted Teen Killer of Maddy Middleton Denied Freedom By Judge, Will Stand Trial to Determine His Fate