Elementary School Music Teacher, 27, Accused of Strangling His Sister-In-Law, 25, to Death Before Sexually Assaulting Her
Joseph Horner is accused of killing and sexually molesting his sister-in-law.
July 1 2026, Published 11:45 a.m. ET
An elementary school teacher who was said to be infatuated with his sister-in-law allegedly strangled the woman to death before sexually assaulting her body, RadarOnline.com can report.
Authorities claimed Joseph Horner of New York had been fixated with the woman for decades before attacking her while his wife was away on a bachelorette trip.
A Brutal Attack
Victoria Castle was a a PhD student at Stony Brook University.
Horner, 27, lived in an upstairs apartment in the same home with Victoria Castle. According to police, while his wife was on her trip, he asked the 25-year-old victim to help him move a piano into his apartment.
Once there, prosecutors allege he attacked Castle from behind and placed her in a chokehold until she was unconscious. He then allegedly raped the woman, changed his clothes and called the police.
"The male caller requested police and an ambulance to this location for a deceased female," Det. Lt. Daniel Steller, deputy commanding officer of the NCPD Homicide Squad, said.
Castle was taken to a nearby hospital, where she was pronounced dead.
Horner Was Allegedly 'Obsessed' With Castle
Horner could face life in prison if found guilty.
At his arraignment, prosecutors said that Horner was "obsessed" with Castle for more than a decade before the brutal attack, which allegedly took place in their shared North Massapequa home on June 29.
Horner was charged with second-degree murder and is currently being held without bail, according to prosecutors. He has pleaded not guilty. His lawyer also confirmed Horner has also been placed on administrative leave from his teaching position.
"He's an Oceanside teacher, he's tenured, he's very well loved by his students and his colleagues; these allegations are not very in line with what his community friends and family believe," attorney Gregory Grizopoulos said.
Wedding Day Note of Love
Castle praised her alleged killer and his wife the day of their wedding.
Horner and his wife have been married for three years, and Castle shared a now-eerie tribute to the couple on social media the day of their wedding.
"My sister, my person, my partner in chaos, is now married to one of the most wonderful people in the world," Castle gushed. "I love you both forever!"
The proud sister posted the message alongside a photo of Horner sharing a wedding-day kiss with his new bride.
'Rest in Peace, Victoria'
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Friends mourned Castle online.
Castle's final Instagram post was a collection of photos from her most recent adventures posted just six days ago. One snap was of a sign that read "The best is yet to come."
In the comments section, one user wrote: "Rest in peace Victoria. You were a wonderful person who brightened up every room you entered, you will be missed dearly."
If convicted, Horner faces 25 years to life in prison.
"These are very serious and disturbing allegations, and there's a very stark contrast between the allegations and his beloved reputation that he had as a teacher, with both his students and his fellow teachers," Horner’s attorney said in a statement.
"His family is devastated by the loss of their family member, Victoria, as well as the allegations against their son, Joe. We’ll continue to evaluate the evidence as more details are disclosed to us."
