The teacher allegedly had sex with the boy 28 times during the last week of March, and on at least one occasion allowed the boy's 12-year-old friend to watch, authorities said. She also gave the students alcohol, according to New Castle County Police.
Rachel Holt, 34, a science teacher at Claymont Elementary School, was arrested early Tuesday and charged with rape, providing alcohol to a minor and unlawfully dealing with a child, authorities said.
Acting county Police Chief Lt. Col. Scott McLaren said the boy's father contacted authorities after becoming suspicious that his son was having an inappropriate relationship with his teacher.
Authorities said Holt took the boy out for dinner and allowed him to drive her vehicle.
CBS News affiliate KYW reports that the victim's father became suspicious when the teacher began calling the boy at home and his son lied about staying at a relative's home when he allegedly stayed at the suspect's house.
A telephone message left at Holt's home seeking comment was not immediately returned.
Ellen Marie Cooper, a staff attorney for Brandywine School District, refused to discuss Holt's employment status but said a substitute teacher was conducting her classes.
According to sources, Holt taught at five schools in the area during eight years. Police say it is too early to know if there are other victims, KYW reports.
Holt was arraigned Tuesday morning and is being held on $500,000 bail.