Deadly Sins is a 1995 American-Canadian slasher film directed by Michael Robison, and stars David Keith and Alyssa Milano.
When one of them, an orphaned outsider named Gwendolyn (Telek), is found dead, hanged from the church bells, Seattleite deputy sheriff Jack Gates (Keith) is assigned to the task of the mystery.
Mother Superior (Perry) assigns her secretary and the school's history teacher, nun Cristina Herrera (Milano), to help Jack with the case.
The following morning, Jack learns from Doc that Gwen did not commit suicide, but was murdered: there was a cross sign carved in her stomach after her death.
The next day, Cristina shares her doubt in the integrity of some of the staff with Jack: she finds it strange that Father Anthony graduated top of his class at Harvard and is now teaching at the small Catholic school; Mother Superior supposedly killed her husband in the past - she is unable to find out, however, why Headmaster Gray left his previous school eight years earlier.
Jack has recently found out that Headmaster Gray, previously known as Marc Anthony, was arrested in Webster, Illinois for having sex with one of his students; the charges were later dropped.
After they escape the tunnel, they conclude that Gwen killed herself all along and did not become the surviving main character of the film, because she was the only girl who had a creature with no account for a sin and thus could not have been a victim of the murderous Emily, who also gave birth to a stillborn baby child.