A man who died of a drug overdose after racking up arrests for assault and attempted murder and other crimes has been linked to a decades-old California cold case murder through DNA and genetic genealogy.

Vallejo police said they identified Naomi Sanders’ killer on Thursday -- the exact day her body was found 47 years ago.

Sanders was 57 at the time of the 1973 murder and managed the apartment complex where she lived. She lived alone and was raped and strangled in her apartment.

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Police said in a news release the man who killed her was Robert Dale Edwards, who was 22 at the time. His father worked with Sanders.

Police said Edwards was identified after DNA from the crime scene was uploaded to GEDMatch, a public genealogy website by Parabon NanoLabs, which conducts genealogy research.

The crime scene DNA was recovered after forensic testing in 2014 on clothing Sanders was wearing when she was killed, they said. There were no matches when the DNA profile was entered into the FBI's DNA database of convicted criminals.

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DNA collected from a man who was Edward’s biological son confirmed the match, police said.

“The question that had gone unanswered for over 46 years was now answered,” police said in a news release.

Edwards died of a drug overdose in Napa County in 1993.

His criminal history also included DUI, domestic violence and theft in addition to attempted murder and assault, police said.

During its research, Parabon came up with the name of another person who was ruled out as a suspect when police went to Louisiana and obtained his DNA.

Two nieces of Sanders, Sharron and Dixie Kadinger, thanked police in a statement for bringing the family closure.

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"May Naomi now rest in peace," they said.