DERRY, N.H. (AP) – A newborn girl delivered after her pregnant mother was killed in a Derry car accident has also died.

The baby girl, Rachel Lee Stanley, was pronounced dead Sunday evening at Massachusetts General Hospital, where she was being treated. Doctors delivered the girl after her pregnant mother, Tonya Wells, 24, died Aug. 8.

Joseph Stanley, Wells’ boyfriend, and the father of her baby, told police the two were arguing when the nine months pregnant Wells opened the door of a pickup truck and threatened to jump. He said Wells fell out of the truck and it ran her over.

Police said previously they would not file charges in the death. The accident remains under investigation.

Stanley and Wells also had three boys together, aged 5, 3 and 1.