Then, in 2008, investigators extracted a DNA profile from the remains. But, the police said, the DNA failed to lead to a match after it was entered it into a national database.
In February 2017, the police sent the sample to a Virginia company, Parabon NanoLabs, where a forensic artist, Thom Shaw, used the sample to create a sketch of the victim. The lab also mapped her potential family tree.
In 2019, a police officer in Montgomery County, Md., Steven Smugeresky, took over the ancestry research and worked tirelessly to develop leads on the identity of the remains, the police said. The New Castle County Police followed up on those leads and obtained DNA samples from possible relatives.
Mr. Heiser said he got a call about two months ago from an investigator who asked him for a DNA sample and explained, “We think we might have found your mother’s remains.”
“It was a shock to us,” he said. “You’re never expecting a phone call like that, ever.”
A few weeks later, he said, the police called him again to say the remains had been conclusively identified.
“You’re thinking, ‘Well, as horrible as this story is, there’s some closure,’” he said. But the discovery has also raised more questions, he said, about who might have killed his mother.
“Before, we wondered where our mother was,” he said. “Now, we’re wondering what happened to our mother. So one door closes, another opens.”
Sheelagh McNeill contributed research.