It was the promise of youth and the sustained mystery surrounding the unidentified body of a 4-year-old found just more than a month ago on Deer Island that has so gripped millions of people, according to the national forensic specialist who is assisting police with the ongoing “Baby Doe” case.

Carol Schweitzer, a senior forensic case specialist with the National Center for Missing and Exploited Children, told the Herald that she works cases across the eastern half of the United States, but this one stands out.

“The public is really relating to it,” Schweitzer said. “This is the case for 2015. She was just found. She just died. The community is trying to process what that means for them.”

Schweitzer’s group has helped police in Massachusetts prioritize and fill out tips into leads, do a deeper analysis of DNA, and pursue a special chemical analysis that could tell investigators where Baby Doe spent the last few months of her life.

On June 25, a woman walking her dog on Deer Island called police after finding the girl’s body in a trash bag, with no signs of trauma. Police believe the girl was about 4 years old.

The still-unidentified child, being called Baby Doe, has prompted tens of thousands of tips, many on leads from across the country and a few from as far flung as Europe, police said.

The composite photo of what the girl would have looked like, created by Schweitzer’s missing children organization, has been shared hundreds of thousands of times and viewed 54 million times since its initial posting.