Investigators said then learned that the relationship was sexual in nature.
On Monday morning, Parker was taken into custody and questioned at the Clark County Jail. Parker was then charged with four counts of sexual battery and booked into the jail.
Schools said Parker has been placed on administrative leave without pay. He has been with the district for seven years and taught Social Studies.
Clark County Sheriff Gene Kelly said, "This is a man who is in a position of trust in a school. He has violated that trust."