They hope showing how some victims looked when they were alive will help solve how they died.
To do it, they're reconstructing skulls to create recognizable faces.
One such skull, that of a woman found in 1997 in southern Delaware, rests at the medical examiner's office in Wilmington. Her death remains a mystery.
Now, the medical examiner is hoping to take a fresh look at old, but not forgotten, cases.
"These faces that you see here represent somebody's loved one, it's somebody's mom or sister or daughter," said Deputy Medical Examiner Hal Brown. "And somebody out there is grieving."
Brown wants to end the grieving and solve these cold cases. He's hoping forensic and DNA advances will help.
He's also hoping someone out there will know more about these cases, including one in which a woman's head was found in field with red letters painted across her jaw.
"The letters E and L were visible," Brown said. "It clearly tells me that the remains of this woman were not treated with dignity and respect."
There are about two dozen mysteries yet to be solved, and those at the medical examiner's officer won't rest until they are.
If you have any information, you can call investigators at (302) 577-3420.