This week, investigators identified the remains as those of Evelyn Colon, 15, of Jersey City, Pennsylvania State Police said.
Evelyn's killer has also been identified: Luis Sierra, a now-63-year-old Queens, NY man, who has been charged with homicide, police said.
Evelyn was nearly nine months pregnant when her remains were found along the Lehigh River in East Side Borough on Dec. 20, 1976, investigators said after piecing together the mystery.
Her remains -- along with a nearly-full-term fetus -- were found in three suitcases under an Interstate 80 overpass, they said.
Sierra, of Ozone Park, was 19 years old at the time of the crime, police said. He was being held in New York, pending extradition to Carbon County, PA.
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