After more than 40 years, officials have identified a boy found dead in Long Beach in 1978.

Using a DNA sample, investigators learned that the body was that of 15-year-old Kenneth Nevada Williams, who had run away from his home in La Puente, according to a news release from the Long Beach Police Department.

He had never been reported missing, but by using genealogy, detectives tracked down living relatives of Williams, who then confirmed the boy’s identity.

While the events that led up to Williams’ death remain unknown, police said they have ruled out convicted serial killer Randy Kraft, who was possibly connected by circumstantial evidence but “ultimately ruled out as a suspect.”

“A teenager who went missing in the 1970s has been known only as ‘John Doe’ for decades until recent technology and dogged investigators led to his true identity,” said Donald Alway, the assistant director in charge of the FBI’s Los Angeles Field Office. “Justice delayed doesn’t have to be justice denied in this case. Kenneth Nevada Williams is now a known victim and identifying his killer is the next step in solving this case.”

Police are asking for information that might lead to Williams’ killer. They also are asking anyone who knows about Williams or his whereabouts from Oct. 27, 1977, to June 3, 1978, to come forward.

If you have information, you are urged to contact the LBPD Homicide Detail, Missing Persons Section at 562-570-7246.

Anonymous tips may be submitted through Crime Stoppers by calling 800-222-TIPS (8477) or by visiting lacrimestoppers.org.