Three people, including a U.S. Air Force member and a pair of siblings, have been arrested and charged in connection with the fatal shooting of a college student over the weekend, authorities have said. Jessica Quintanilla, 21, is charged with fatally shooting 19-year-old Leilani Beauchamp, at the Solano County home of Juan Parra-Peralta, 20, the airman. Parra-Peralta is charged with accessory to murder, as is Quintanilla’s 27-year-old brother, Marco, 27.

Prosecutors said they believed Quintanilla and Parra-Peralta were in a romantic relationship at the time of the homicide. “This appears to be a love triangle situation,” one said. The homicide is believed to span three counties. Beauchamp was seen leaving a Halloween party in Sacramento County early Saturday morning with Parra-Peralta and one other airman. Her remains were recovered Sunday evening in Monterey County. Beauchamp’s grandmother, Monica Beauchamp, told CBS13 that her granddaughter knew Parra-Peralta and had been to his home before. “She didn’t leave a party with people she didn’t know,” the grandmother said. Parra-Peralta has posted bail and is back on base under supervision. The Quintanillas are slated to appear in court for a full arraignment on Thursday.