A schoolteacher who was reported to have been having an affair with an underage student has been gunned down on Mother's Day.

Authorities say 32-year-old Rachael DelTondo had gone to an ice cream shop on Sunday night and had just returned to her mother’s home when she was shot multiple times.

Ms DelTondo died at the scene, 35 kilometres northwest of Pittsburgh. Police have ruled the death a homicide.

Ms DelTondo died at the scene, 35 kilometres northwest of Pittsburgh. (Nine)

"I counted six shots that I heard," neighbour Fred Poore told local media.

Authorities have not released further details, citing an ongoing investigation.

Ms DelTondo was suspended last November from the Pennsylvania Cyber Charter School.

Ms DelTonda is pictured with her partner in 2015. They called off the wedding after the affair. (Nine)

The suspension came after school officials received an anonymous email containing a February 2016 police report stating Ms DelTondo had been found in a parked car with a 17-year-old former student.

The report said she was busted with the teenager at 2am.

"The windows were steamed over and the engine was not running," police noted in their report.

Police have ruled the death a homicide. (Nine)

She begged officers not to tell her fiancé "because he would get mad". He eventually called off the engagement.

No charges were ever filed over the relationship.

Brian Hayden, chief executive officer of the Pennsylvania Cyber Charter School, said he was “saddened” by the death.

No charges were ever filed over the relationship. (Nine)

"We were saddened this morning to learn of the tragic death of Rachel DelTondo, apparently the result of a violent incident in the City of Aliquippa," he said.