In 1975, Clinton, Iowa sheriff's deputies responded to a report and found a dead teenager in the Mississippi River, but she could not be identified.
After an autopsy, the death was ruled a homicide.
The Clinton Sheriff's Office now says Cheryl Lynn Edwards of Waukegan was positively identified through forensic genealogy.
Iowa officials says the new technology means the homicide investigation can proceed.
Cheryl Lynn Edwards' family has been notified.
The Waukegan Police Department and the Iowa Division of Criminal Investigations are asking for any information regarding her disappearance and death 51 years ago.
