At Larry Maretto's burial the Catholic priest says "in nominis patris et filius et spiritus sanctus," getting most of the endings wrong. Correct is "in nomine patris et filii et spiritus sancti," which any priest would know.
This story takes place in Little Hope, NH. Early in the movie, a newspaper article entitled "Sex, Violence and the Weather" shows a map of southern New Hampshire, with an arrow pointing to Little Hope. But the arrow actually points to a location in Massachusetts.
Lydia says that Suzanne let her drive her car even though she did not have a learner's permit. New Hampshire does not issue learner's permits. Anyone at least 15 1/2 can drive if accompanied by a licensed driver at least 25 years of age.
On the night that Larry is murdered, Suzanne, her parents and Larry's parents are all shown sitting inside the apartment where he was shot. As a murder scene, it would have been taped off for forensic examination. There is no way it would have been contaminated on that level. It would have been at least a week before anyone outside of the CSI team were allowed in.
At the end of the movie when Janice (Illeana Douglas) is skating on the frozen pond, she is very unsteady on her skates like someone who has not been skating long. Janice skates out of the frame and then skates back into the frame, however, it is clearly another, more experienced skater.
When Lydia calls Suzanne to set up the last meeting, we see a large device taped to her abdomen. At the mall, with the detectives listening, Suzanne pokes Lydia in exactly the same spot, but neither she feels nor do we see the device under Lydia's shirt.