A teenager whose body was dumped at Fort Indiantown Gap, a human skull discovered near a York County mall, and a dismembered torso left on the side of a road in the eastern Poconos - all horrible crimes - with one thing in common: the victims remain unidentified.

But there is a new effort, a collaboration between state police and researchers from the University of South Florida, to attempt to identify the victims of some of Pennsylvania's best-known cold cases. One of them is the unsolved murder of 'Beth Doe,' whose remains were found in suitcases dumped along Interstate 80 near White Haven.Earlier this week, researchers from USF's Institute for Forensic Anthropology and Applied Science, led by Dr. Erin Kimmerle, traveled to Luzerne County to exhume the bodies of four unidentified cold case victims. They hope to apply modern forensic methods to cases that are as much as 40 years old, and possibly identify the victims."There are thousands of homicides across the country that simply can't be solved until the victims can be identified. By some estimates there are as many 40,000 unidentified bodies across the United States," Cpl. Thomas McAndrew, who invited the researchers to Pennsylvania.The researchers use methods that were not available when the cases were investigated, like DNA analysis - cross-referencing with the DNA of known missing persons. They will reconstruct the face of a victim to see if it triggers the memory of anyone who knew the person.They also perform chemical isotope testing, which can give an idea of the geographic area where a person spent their lives.The information will also be put in the National Missing and Unidentified Persons System."In each (missing persons) case there are family and friends who knew that person, and are left in limbo not knowing what happened to them," she said.In addition to the bodies exhumed this week, Kimmerle has been working on identifying five other victims from Pennsylvania who are cold cases.The one best known to local residents would be 'Beth Doe,' a female homicide victim whose remains were found on Dec. 20, 1976, near White Haven, where Interstate 80 crosses the Lehigh River. The victim, a pregnant female believed to have been between 15-25 years old, was dismembered and stuffed into suitcases before being thrown from the highway.Her body was actually exhumed in 2007. A facial reconstruction was done, as well as chemical isotope testing.The other ongoing cases took place in Monroe, Lebanon, Luzerne and York counties. In each of those cases, facial reconstruction and chemical isotope testing were conducted - except for one. The Monroe County cases involves a torso - with no arms, legs or head - found in Paradise Township in 2011.The bodies exhumed this week were all discovered between 1970 and 1980 in the Luzerne County area. They include a black female found along I-80 in 1973, a black female found along I-81 near Nuangola, a white male found in 1979, and a newborn infant found in the trash in Larksville Borough in 1980.McAndrew said that while the odds of solving a 40-year-old cold case are slim, it has happened before. He was one of the officers who worked on the case of Richard Keiper, who was arrested and convicted of a 1968 murder in Monroe County more than 40 years later."It certainly makes it more difficult, but it's not beyond reality," McAndrew said.They plan to announce the results of those investigations in the near future.Anyone with information about the cases is asked to contact Crime Stoppers at 1-800-4PA-TIPS, or submit tips at

http://www.crimewatchpa.com/crimestoppers.