Kostial was last seen stopping at the door of a bar in Oxford Square in Oxford, MS, but not going in, police said. Her roommates told authorities she went home around midnight, but left the house again at some point.
The Lafayette County Sheriff’s Department said deputies discovered Kostial's remains while on routine patrol in a remote area near Harmontown, MS.
Police have yet to provide additional details. Multiple agencies are assisting with the active investigation, led by the Lafayette County Sherriff's Department, including the Oxford Police Department, the University of Mississippi Police Department, the Mississippi Bureau of Investigation, and the Bureau of Alcohol, Tobacco, Firearms and Explosives.
"The Sheriff’s Department and Mississippi Bureau of Investigations are following several leads at this time," Maj. Alan Wilburn said, according to local media reports. "We will release more information at the appropriate time."
Kostial, originally from St. Louis, was a marketing student at the University Of Mississippi set to graduate in 2020. In a Facebook post on Sunday night, her father Keith Kostial confirmed news of her death. "Yesterday, Saturday afternoon, we were visited by the Sunset Hills, MO, police who communicated to us that our beautiful dear Alexandria (Ally) Kostial was the victim of a homicide," he wrote. He added that his daughter had been taking summer courses and teaching fitness classes. Kostial's family has started a GoFundMe for her funeral expenses.
Kostial's sorority sisters in the school's Alpha Phi chapter also paid tribute to her on social media.
"Still can't believe this is real," her friend Kassidy Desnoyer wrote on Facebook. "I’m so grateful that I got to know Ally throughout high school and we shared so many memorable experiences at Ole Miss together. From road-tripping down to Oxford to being my Alpha Phi sister, I will cherish all the memories we had together. She was the brightest light and always had a smile on her face. She truly was a ray of sunshine. My heart and condolences go out to the Kostial family."
If you have information about Alexandria Kostial's death, you can contact the Lafayette County Sheriff’s Department at 662-234-6421 or Crime Stoppers at 662-234-8477.