A Mother's Revenge (aka Desperate Justice) is a 1993 American film starring Lesley Ann Warren, Bruce Davison, and Shirley Knight.
Frank is later arrested after the police discover he had two prior molestation charges in California, something the school claim they were unaware of before hiring him.
While detectives assure Bill they have a slam-dunk case, a number of discrepancies soon come to the surface in court, culminating in a solid alibi from Frank's mother, Bess, who testifies that her son was dining with her in a restaurant when the crime occurred.
Meanwhile, Carol's trial finally begins; she fights to prove that she had lost control of herself in the moment she shot Frank, and had no intentions of actually killing him.
As the judge prepares to hand down her sentence, Bess, who had been watching from the back of the courtroom, comes forward and admits she lied to protect her son, thinking the courts could prove Frank's crime without her help.