A Pennsylvania nun who was physically and sexually assaulted last December forgave her attacker and prayed for him ahead of his sentencing on Wednesday.

The 86-year-old victim did not appear in the Beaver County court, but her written statement was read by another sister.

The Sisters of St Joseph of Baden nun was walking through the parking lot of St. Titus Church in Aliquippa on December 13 at 11:30am, trying to put newspapers in a recycling bin.

Andrew Bullock, 19, approached her, and asked if she needed help. He then exposed himself, grabbed her by the throat, and choked her on the ground. Bullock raped her and punched her in the face, breaking her jaw.

Police matched his shoes with footprints found in the snow at the scene, and he admitted to the crimes.

Despite being a victim of a horrific crime, the elderly nun's statement was one of compassion and hope for the young man.

"You, Andrew, are my brother, and you, like me, are a beloved child of our heavenly Father God," she wrote. "And our Father asks of his children to love one another and forgive one another. And, this I do, Andrew, by God's merciful grace.

"My profound and permanent prayer for you, Andrew, is that you wholeheartedly take advantage of the educational, uplifting, socially positive opportunities that may be available during your prison time," she continued.

"I pray that one day both of us can look back upon what happened and understand even more truly, that, as Scripture says: 'All things work together unto good for those who love God.' Learn to love God ever more, Andrew, for He certainly loves you and yearns for you to have a healthy, holy and happy life."

Bullock was sentenced to 18 1/2 to 37 years in prison.