On the night of October 5, 2015, 18-year-old Sierra Gregoire was shot on State Street in LaPlace, Louisiana. She was with her 23-year-old cousin Travis Gregoire and a friend, Damarius Carter, when a white four-door pickup truck pulled up and someone inside opened fire. Travis died at a local hospital that morning; Sierra was taken to University Medical Center in New Orleans and died that evening. Carter survived his wounds.

Investigators found a burned-out white pickup in nearby Reserve that they believed was linked to the attack. Authorities later said physical evidence tied 26-year-old Djuan Mackey of Gretna to the double homicide; he was arrested in May 2018 and booked on two counts of second-degree murder and one count of attempted second-degree murder. A grand jury indicted him in July 2018 and court records show proceedings continued into 2021 and 2022. Law enforcement has said they believe the shooting was a case of mistaken identity.

If anyone has information about the night on State Street or the burned pickup found in Reserve, please come forward.