Trigger Warning: This article contains references to the alleged se–-ual abuse, murder, and violence that some readers may find distressing.

Long Island music teacher Joseph Horner is accused of meticulously planning the murder and s*xual assault of his 25-year-old sister-in-law, Victoria Castle. According to prosecutors, Horner even practiced applying a chokehold on a stuffed animal before carrying out the gruesome crime. But this wasn’t the only horrific detail.

Prosecutors allege Horner had been fixated on Castle for years and deliberately asked her to help him move a keyboard while his wife, the victim’s sister, was out of town. They also allege that he repeatedly broke into the victim’s apartment to access her electronic devices in hopes of finding explicit photos of her.

According to the indictment, Horner answered a FaceTime call from his wife during the attack and pretended as though nothing was wrong before s*xually assaulting Castle. The victim, a Ph.D. student at Stony Brook University, lived one floor below her sister’s apartment in the family’s North Oak Street home.

Assistant District Attorney Alexander DePalo said in court, “This defendant saw an opportunity to follow through on his s*xual desires to be with the victim, a woman he admitted to lusting over since 2017.” DePalo also added that Horner attacked Castle from behind, held her in a chokehold, and waited for her to become limp before s*xually assaulting her.

According to prosecutors, Horner remained at the home after the attack and waited for responding officers at the front door. He was arrested by the Nassau County Police Department’s Homicide Unit while Castle was taken to St. Joseph’s Hospital, where she was pronounced dead. The medical examiner determined the cause of death was strangulation. According to the Nassau County District Attorney’s Office, a grand jury indicted Horner on July 29, 2026, charging with first-degree murder, two counts of second-degree murder, and two counts of first degree r–.

Horner pleaded not guilty in court, while his attorney has not publicly commented on the allegations. Nassau County DA Anne Donnelly said during a press conference, “This vicious attack was the act of a deranged individual suffering from an unrequited love and sick lust dating back more than a decade.”

The news of the disturbing crime has garnered national attention, sparking extreme public outrage. Social media users expressed shock on various platforms, while many hoping for a death penalty in the case.

 

One Instagram user commented, “Sick sick man. His poor wife and her family.” One more posted, “Life in prison isn’t enough punishment.” An X user commented, “Planned for years and even practiced the method? That’s deeply chilling. The allegations are incredibly serious.”

Another one added, “That isn’t just a crime; that’s pure premeditated obsession. Real life is scarier than any thriller movie.” Horner is scheduled to appear in court on August 19. He may get life in prison if convicted on all the charges. He’s currently being held at the Nassau County without bail.

Disclaimer: The Inquisitr could not independently confirm the facts of this incident and is reporting based on the information available within the public video record.