"Finally everyone knows who Beth Doe is. It's so important in a case like this," said Shawn Williams, a retired Pennsylvania State Police homicide investigator.

Williams and Tom McAndrew, another retired PSP investigator, are two of the more than 100 officers who have worked to solve the case of "Beth Doe" over the last 44 years.

"It's bittersweet, I mean the facts of this case are horrible but at least that family knows where their loved one is," said McAndrew.

On Wednesday, state police revealed new details in a news conference about how this cold case was cracked. Authorities say while the remains of Evelyn Colon and her full-term daughter were found in 1976, it took awhile for them to make progress.

"DNA evidence didn't come about until the 90's. We mostly received tips, followed tips on different missing persons and attempted to identify them as Ms. Colon. All of them were discounted after investigation," said Lt. Devon Brutosky of the Pennsylvania State Police Criminal Investigation Section.

For decades, investigators tried to find answers, entering her information into numerous missing person databases and even exhuming her body in 2007 to extract DNA.

"Shawn and I made the decision that we were really going to give this the best effort we possibly could," said McAndrew.

Late last year, those DNA samples were ultimately sent to Othram, a one-of-a-kind forensic lab in Texas which works with law enforcement to solve cold cases.

"We were asked to build a profile that represented the DNA markers of Evelyn," said David Mittelman, CEO of Othram.

Mittelman explains it was their genetic profile, along with the persistence of state police, which led to the DNA match with Evelyn's nephew, Luis Colon Jr., last month.

"44 years, most people have moved on, the world kind of continues to turn but the family doesn't move on, they were always waiting," said Mittelman.

Luis Sierra, Evelyn's alleged killer, is being held without bail in the Carbon County Correctional Facility. Right now he's charged with one count of criminal homicide.

Carbon County District Attorney Michael Greek says 1976 law did not allow for homicide of an unborn child, but prosecutors are researching to see if other charges might apply.