Circle of Friends (2006)

Maggie is a 30-year-old New York City career woman who returns to her hometown in upstate New York for a funeral of an old friend, and becomes reacquainted with three old high school friends, Joan, Susan, and Emily, as well as her old boyfriend Harry. When Maggie learns that other people whom she knew in school are dying mysterious deaths, she tries to convince her friends and the skeptic police that the murders are somehow connected to one another and linked to a mysterious death in school. When Maggie herself nearly becomes a victim of the unseen killer, she must dive into her past to uncover some terrible secrets that her friends may be hiding from her, which leads to one or more of them who may be the killer.