Detectives in Maryland are having a bone from a 1972 victim of a serial killer tested in an effort to identify the woman.

Prince George's County police sent the 19-year-old woman's femur to a lab in Virginia for DNA testing.

Last year, 79-year-old Samuel Little sketched a drawing of the young woman he says he killed, but she remains unidentified.

Little and the woman are believed to have met at a Greyhound bus station on New York Avenue in Washington, D.C., in May or June 1972. Over a three-day period, Little and the woman had interactions and at one point, left the station in Little's car, Little told authorities. They drove on what investigators believe was the Baltimore-Washington Parkway, left the parkway in the area of Beltsville, Maryland, and had sex, Little told authorities.

He then strangled the victim, he said.

The woman's remains were found in December of that year by a hunter who was walking through a wooded area. A medical examiner concluded that the remains had been there for about six months.

Little was in the D.C. area at the time of the killing and was arrested on a handgun charge in May 1972 at the same bus station where he said he met the victim.

She may have been from the Massachusetts area and had recently gotten divorced, Little told investigators. Her height was between 5-foot-2 and 5-foot-6. She was Caucasian and may have had a child.

Little, also known as Samuel McDowell, was already serving three life sentences for strangling three women in the Los Angeles area from 1987 to 1989 when he confessed to more than 90 killings across the country. The FBI verified 50 of those deaths, making Little the most prolific serial killer in U.S. history.

Little told investigators that the Prince George's County victim was his only victim in the Washington, D.C., area.

Prince George's County does not plan to prosecute Little because he is already serving three life sentences.

Anyone with information that could help investigators is asked to call police at 301-772-4925. If you wish to remain anonymous, call Crime Solvers at 1-866-411-8477.