Hallowed Murder by Ellen Hart

When University of Minnesota student Allison Lord is found drowned in the icy waters of the Lake of the Isles, the local police are quick to rule her death a suicide. However, Allison's grieving sorority sisters refuse to accept the verdict and urge their alumni advisor, Jane Lawless, to investigate. Guided by her own sharp instincts and accompanied by her theatrical, larger-than-life best friend Cordelia Thorn, Jane starts chipping away at the victim's seemingly perfect life. She uncovers a hidden landscape of secret campus trysts, religious fanaticism, and family disinheritance threats, risking her own life at a remote vacation lodge to catch a calculating killer before they strike again.