State police arrested a 24-year-old Massachusetts teacher late Monday night after finding her in a Morgantown-area motel room with one of her eighth-grade students.

Acting on an arrest warrant out of Holyoke, Mass., police charged Lisa Lavoie with enticement of a child, a felony offense that under Massachusetts law includes statutory rape.

The 15-year-old boy, a student at Maurice Donahue Elementary School, was unharmed and will be returned to his parents in Massachusetts.

The Post-Gazette does not identify victims in sexual assault cases.

Holyoke Police Chief Anthony Scott and school officials said the case began on Feb. 13, when the boy's mother complained to the Holyoke School District that her son was having an improper relationship with his teacher.

Holyoke Mayor Michael Sullivan, president of the school board, said the relationship apparently grew out of an after-school program that was less structured than the classroom environment.

He said there is no evidence that the two had sex at school and they were never alone together. But a bond had developed over the last two months from social interaction after school.

"It's like a two-hour recess," Mr. Sullivan said. "We're looking at ways to change the program."

When the parents complained, he said, they were not overly concerned and did not indicate that the relationship was sexual. They were told to fill out the necessary forms, but school officials didn't talk to Ms. Lavoie because she'd already left for the day as the school went on a one-week break.

Three days later, on Feb. 16, the mother called police to say her son had disappeared. Ms. Lavoie also didn't show up for work that day, and her family filed a missing persons report in Ludlow, Mass., where she lives.

Chief Scott said his detectives used financial and cell phone records to track Ms. Lavoie to two hotels in Vermont late last week.

Working with the district attorney's office, police on Monday night then traced her to the Super 8 motel at the Glenmark Center off Exit 7 of Interstate 68 outside of Morgantown.

Detectives called state police in West Virginia, who entered the room at about 11 p.m. and found the teacher and student.

Chief Scott said the charges are based on those facts and on the accounts of several witnesses in Massachusetts, identified by Mr. Sullivan as fellow students of the boy, who told police that the two were having a sexual relationship.

Ms. Lavoie was being held yesterday in West Virginia pending extradition to Massachusetts. A first-year teacher, she has been placed on administrative leave pending outcome of the case.