An Oceanside School District music teacher is accused of fatally strangling a woman whom he has known for a decade in North Massapequa.

Today, Nassau County police said they arrested Joseph Horner, 27, and charged him with second-degree murder.

According to investigators, officers responded to 285 N Oak Street around 8:45 a.m., Monday, after Horner called 911 to request an ambulance for a female victim.

Police said they found Horner outside the home when they arrived.

Officials said the home was multi-family and split into two apartments; Horner and his wife, who was not home at the time and uninvolved, lived upstairs and the victim lived on the ground level.

Inside, police said they found the female victim on the floor of that ground-floor apartment. She was taken to the hospital, where she died at 9:25 a.m., according to officials.

Police have only identified the victim as a 25-year-old woman who was a PhD student at Stony Brook University. Investigators said that Horner and the victim met when Horner first met his wife in 2016, but would not disclose the relationship between the suspect and the victim or a possible motive.

Nassau County police said Horner acted alone and had no prior interactions with law enforcement or previous arrests.

The investigation shut down the Nassau County neighborhood for 12 hours between 9 a.m. and 9 p.m. Monday.

In a statement, Oceanside Superintendent of Schools Phyllis Harrington told News 12: "According to the Nassau County Police Department, a staff member in the Oceanside School District was recently arrested on charges of homicide. Nassau County Officials indicated that these charges have no connection to the school district or its students. We understand that this news is deeply disturbing. This staff member has been placed on administrative leave effective immediately, pending further review. We have no further information at this time. The Oceanside School District is committed to maintaining a safe, professional, and trustworthy environment for our students, staff, and community. We stand by that commitment at all times."

Nassau County police charged Horner with one count of second-degree murder. He is facing up to 25 years to life if found guilty.

He is scheduled to be arraigned later today.