Police say a Vermont woman charged with killing a social worker and three of her relatives after she lost custody of her 9-year-old daughter may have recorded her intentions.

Police want to search the voice recorder that they say was found in Jody Herring's purse after she was taken into custody for the shooting of Department for Children and Families worker Lara Sobel outside a state office building Aug. 7.

Police say a woman parked next to Herring said she saw Herring talking to herself alone in her vehicle before Sobel was shot.

Herring has pleaded not guilty to shooting her aunt and two cousins in their home in nearby Berlin before shooting Sobel in Barre. Police say Herring thought they had reported her to DCF.