Pamella Jackson Cheryl Miller South Dakota car crash cold case
Pamella Jackson and Cheryl Miller died in a car crash in 1971National Missing and Unidentified Persons Database

US authorities have confirmed that the human remains found in a car unearthed from a South Dakota creek during a drought in 2013 were of two teenage girls who disappeared more than 40 years ago.

Officials in the midwestern US state said that DNA tests and personal items recovered from the 1960 Studebaker Lark wreck left them with no doubt that Cheryl Miller and Pamella Jackson died in a car crash on their way to an end-of-school-year party in May 1971.

The disappearance of the two 17-year-old students at Vermillion High School has haunted their families for decades.

Attorney general Marty Jackley said the bodies were found in the front seats and everything suggested they died in a crash. No foul play was suspected.

"It's consistent with a car accident," Jackley said. "To start with, the forensic pathology and anthropology reports indicate that there's no type of injury that would be consistent with or caused by foul play or inappropriate conduct."

Jackley said that the car was in the highest gear and the headlight switch on the dashboard showed the lights were on.

The rusty vehicle was discovered half submerged in Brule Creek near Elk Point.

Family members and security forces had searched the area countless times after the girls were reported missing.

Jackson's father, Oscar, died five days before the car was found.

In 2007 a classmate of the two girls, David Lykken, was charged with two counts of murder.

Charges against the man, who is serving an unrelated 227-year sentence for rape and kidnapping, were dropped.

"Our day has come through this journey for answers pertaining to our sister Sherry and dear friend Pam, for we will be able to finish the last chapter of this journey," Jackley said reading a statement from the families.