Scientists may be onto another break in figuring out the identify of Baby Doe. 

According to the Suffolk County District Attorney's Office, researchers are using stable isotope ratio analysis, which compares residual oxygen isotopes in human hair and teeth with the known levels of drinking water across a wide scale. The lab conducting these tests is located in Utah. 

“Where ever you go you’re drinking water, and so from drinking and eating, you’re taking in water from a local supply and the content changes depending on where you are,” Suffolk County District Attorney Press Secretary Jake Wark said. “These leave residual traces in teeth and hair. It’s the same general idea with the pollen test, but that’s more external while this is a more internal version of the same theory.”

Pollen tests suggested that she either spent a great deal of time in, or was from, the Greater Boston Area. In light of this evidence and the fact that her body did not show signs of advanced decomposition when it was found, investigators believe she died somewhere in the area rather than in a distant location, the DA's office said. 

RELATED: Pollen test indicates Baby Doe came from the Greater Boston Area

The National Center for Missing and Exploited Children facilitated the tests and which also created the widely-distributed composite image depicting the girl as she may have appeared in life. These images have been plastered around the city, distributed all over the social media world and have appeared on billboards all over the state. 

A woman walking her dog along the western shore of Deer Island found the little girl’s body in a trash bag at the waterline on the afternoon of June 25. She is believed to have been about 4 years old, had brown eyes and brown hair, weighed about 30 pounds and stood about 3-and-a-half feet tall. She was wearing a pair of white leggings with black-and-white polka dots and was found with a zebra-print fleece blanket that investigators believe may have been special to her.

RELATED: Officials: Help us ID 'Baby Doe' found in a trash bag on Deer Island

Since that time, State and Winthrop police have received about 150  leads as to her identity, conducting and coordinating well-being checks in 35 states and internationally. None have led to an identification, but investigators are confident that they will learn her true name, possibly from a person who knew her but has so far been reluctant to come forward.