(CBS/AP) SIOUX FALLS, S.D. - Authorities have found an old Studebaker believed to be related to the 1971 disappearance of two 17-year-old South Dakota girls, officials said Monday.
South Dakota Attorney General Marty Jackley and Union County Sheriff Dan Limoges said the car recovered from an embankment in Brule Creek is believed to be related to the disappearance of Cheryl Miller and Pamella Jackson. Jackley said the vehicle will be processed for forensic evidence. He said he could not comment on whether any remains were found inside the car.
The girls were last seen on May 29, 1971, driving a beige 1960 Studebaker Lark on their way to a party.
According to CBS affiliate KELO, an area resident called authorities after noticing one of the car's wheels sticking out of the creek.
High spring water levels followed by a drought this summer helped reveal the old car, and authorities recovered a Studebaker hubcap and a license plate matching the car once owned by Miller's grandfather, Jackley said.
"The excavation is ongoing," Jackley said Monday evening. "We're taking every precaution that we can to preserve the evidence so we can glean whatever forensics can tell us."
Dexter Brock, Jackson's brother-in-law, said the news came to family members Monday morning just two days after they buried Pamella Jackson's father, 102-year-old Oscar Jackson. Relatives were just getting ready leave the Brocks' house in Sioux Falls to head home when the phone rang.
"They called us this morning and said they found the car, and that's about all we know," he said Monday afternoon.
A man already serving a prison sentence on unrelated charges was indicted for murder in the deaths of Miller and Jackson in 2007, but the charges were dropped after prosecutors found out that a supposed confession given to a fellow inmate was faked.
The disappearance of the Vermillion High School juniors was one of the initial investigations of South Dakota's cold case unit, which was formed in June 2004 to focus on unsolved suspicious deaths and disappearances because there's no time limit on filing criminal charges in homicide cases.
A September 2004 search of a Union County farm turned up bones, clothing, a purse, photographs, newspaper articles and other items, but not the car. Authorities have not ever said if the bones belonged to the girls - or if they were even human remains.
In a warrant authorizing the search, authorities said that David Lykken, who lived at the farm in 1971, might have been involved in the disappearance of Miller and Jackson as well as three other unnamed people. Lykken, 59, is prison serving an unrelated 227-year sentence for rape and kidnapping.
In July 2007, a Union County grand jury indicted Lykken on two counts of premeditated murder, two counts of felony murder and two counts of murder in the disappearance of Miller and Jackson. He was arrested at the prison and scheduled for a March 2008 trial, but state prosecutors dropped all six murder charges after discovering a prison snitch made up a supposed admission.
Aloysius Black Crow pleaded guilty in March 2008 to two counts of perjury for lying to a Union County grand jury and at a court hearing. He had conspired with another inmate to tape a fake confession implicating Lykken.