By Matt Petrillo

BENSALEM, Pa. (CBS) — It’s a decades-old case that has stumped investigators for years. But now, police have identified a pregnant teen girl who was found dead more than 30 years ago in Bucks County.

Bensalem Police admit the investigation stalled for years, but technology kept moving forward. So after creating a family tree based on the victim’s DNA, investigators have now identified her as Lisa Todd, of Philadelphia.

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“I believe we had a full skeleton of her in the well,” Bensalem Public Safety Director Frederick Harran said.

Police say it was 1988 when someone walking by the old Publicker Distillery on State Road in Bensalem found a decaying body inside a well.

The only clues left behind were the victim’s clothing, like her shoes, and her skeletal remains. She became known as Publicker Jane Doe.

“If someone dies in Bensalem we’re gonna want to identify them,” Harran said.

Never giving up, a team of genealogists recently used the victim’s DNA, along with ancestry companies like 23and Me to build the victim’s DNA. That led detectives to identify her as 17-year-old Lisa Todd, who was pregnant at the time of her death.

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Then detectives confirmed it with her family.

“After I summed it up, I said, ‘Do you have a sibling that vanished or disappeared?’ And I was told, ‘Yes, I have a sister that disappeared in the fall of ‘85,'” Bensalem Police Detective Chris McMullin said.

McMullin had recently called the victim’s brother and describes how he reacted to the discovery.

“Relieved, surprised, emotional, shocked,” McMullin said.

Authorities stopped short of calling Lisa’s death a murder as they now work to figure out so many unanswered questions.

“Who she was with, whether or not there was any drug or alcohol use, whether this was intentional or accidental, people that could account for her whereabouts and what she was doing. We need the public’s help,” Bucks County District Attorney Matt Weintraub said.

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Police say Lisa initially went missing in 1985, three years before her body was found.