"You send your kids to school and you think they're safe and look, they're not," parent Elizabeth Padgett said.
Dexter is charged with taking indecent liberties with a student by a school guardian following his arrest on Wednesday.
"It definitely needs to stop,” nanny Savannah King said. “That's the problem with social media these days and young children. Sometimes they get into stuff they're not meaning to."
School officials said Dexter was hired at Morgan Elementary on July 27, 2004, and started at Erwin Middle School on Aug. 17, 2005. He taught math and social studies.
Dexter resigned Wednesday.
Dexter's bond is set at $150,000.
In a statement, Rowan-Salisbury Schools officials said “We are sad and heartbroken any time we receive reports of inappropriate conduct toward any of our students.
“We will continue moving forward in keeping safety a top priority in our schools,” the statement said.