Two girls aged 15 and 17 have been charged with manslaughter in the death of a 32-year-old woman on Manitoba's Sandy Bay First Nation.

Roberta Dawn McIvor, 32, was found dead on the First Nation about 190 kilometres northwest of Winnipeg on July 30. Family members at the time said McIvor's body was discovered on one side of a road and her head on the other side. Police have refused to confirm the details.

Roberta McIvor, seen in a Facebook photograph, was found dead on the Sandy Bay First Nation July 30.Roberta McIvor, seen in a Facebook photograph, was found dead on the Sandy Bay First Nation July 30. (Facebook)

Police said Wednesday that the two girls were arrested following a joint investigation involving the RCMP Serious Crime Unit and the Dakota Ojibway Police Service.

Police said their investigation showed that early on the morning of July 30, McIvor's vehicle was stolen from a yard in Sandy Bay while she was sleeping in it. McIvor was removed from the vehicle and fatally injured when the vehicle was driven away.

Both accused are from Sandy Bay and have been remanded in custody to appear in court in Portage la Prairie. One will be appearing Thursday, while the other will make an appearance on Sept. 12.