BURLINGTON COUNTY, New Jersey -- A New Jersey high school special education teacher is under arrest, accused of having sex late last year with a male student who attends the school.Authorities say 30-year-old Alexandra Reiner, of Eastampton, was charged with second-degree sexual assault and endangering the welfare of a child.Reiner, a teacher at Rancocas Valley Regional High School, was taken into custody Tuesday at the Burlington County Prosecutor's Office in Mount Holly. She is being held in the Atlantic County Jail in Mays Landing, which houses Burlington County's female inmates.The investigation began last week after district officials approached the prosecutor's office with information they had received concerning a possible inappropriate relationship between Reiner and the student.Officials said an investigation revealed that the contact happened in December 2018 in Mount Holly and Lumberton.The age of the victim and additional details about the incident are being withheld in an effort to protect the victim's identity.The investigation is being conducted by the Prosecutor's Office and the Mount Holly Police Department.----------