Two elderly women, permanent residents of the US state of Arizona, were found murdered in the car in which they were traveling on a highway in the northern Mexican state of Sonora, the state prosecutor’s office announced, adding that an investigation is underway to find and arrest the perpetrators.

According to the prosecutor’s office, the two women, Enedina N., 72 years old, and Uvaldina N., 82 years old, were found inside a white Nissan Pathfinder that had overturned and was lying on the side of the road yesterday morning.

The victims had dual US and Mexican citizenship, a source at the state prosecutor’s office told Reuters.

The area where the two women were found dead, a section of road that connects the communities of Sonoita and Kavorka, is notorious for violent gangs and migrant trafficking.

The victims were from Kavorka, prosecutors said.

Mexican National Guard and military forces, who rushed to the area after the double homicide became known, spotted a blue Ford F-150 semi-truck a short distance away. Ammunition and an AK-47 assault rifle were found in the vehicle, which had recently been reported stolen, according to prosecutors.