Just getting to Deer Island- takes some doing - you go beyond Suffolk Downs - to Winthrop - then maneuver through an endless maze of tiny streets passing numerous cul-de-sacs. Even the scream of planes taking off from nearby Logan airport are dulled by the sheer beauty of the islands surroundings.

But it will be 4 weeks this weekend since the body of a young girl, thought to be around 4-years-old, was found along a rocky shoreline on Deer Island. In these past four weeks, investigators say they have followed hundreds of clues, but they still don’t know who she is or how she died.

Most people know Deer Island for the MWRA waste eater treatment plant that looms large - but you can take well-marked paths and bike lanes around it. The island is packed with runners, sightseers and cyclists - dog walkers frequently jump down the man-made rock walls and run along the waters edge - it’s there a woman walking her dog found Baby Doe four weeks ago.

Forensic neuropsychologist Robert Mendoza agreed to meet me at the island. He believes someone familiar with the area parked a car at the small public lot, and took one of the paved pathways to a secluded area then either tossed a bag or clamored down a steep slope of man-placed stones - and dumped a child’s body by the waters edge.

As we walked a quarter-mile or so into the beach, Mendoza says “this was probably a point they thought was as isolated as possible,” explaining that the attack was likely “somebody who knew the area” and then disposed of the body by the ocean, where it would go out to sea. “Walking down wouldn’t be difficult day or night— [though] trickier at night,” he says.

Although Mendoza says he wouldn’t rule out an approach by boat.

“But, as we’ve seen today,” he says, “you don’t get a lot of boats coming that close to the shoreline, because it’s because it’s pretty tricky territory for weekend boaters. So, I think it’s less likely, but in theory, that’s possible.”

Currently we know that she was between 3 and 4 years old, with dark hair about 14 inches long. Her ears were pierced but she wore no earrings. She was wearing white pants with black polka dots. Also enclosed in that garbage bag was a small blanket, a zebra blanket.

“The blanket may have been a very personal thing,” says Mendoza “that either a father or mother would have known was important to this child. It’s sort of a sick way to understand that a parent may feel that way at that moment, but it is in fact important in terms of identifying who might be responsible for this.”

Of the 500 or so children murdered each year, Mendoza says 75% of them die at the hands of a parent.

“It is less likely that the child would be abducted and then brought here to be murdered or the body to be disposed of.”

In the past month law enforcement has tracked down dozens of leads and issued a computer generated image of what the child might have looked like. An image that now hauntingly peers out at motorists on 50 billboards across the state .

This child was between three and four years old, a child that age communicates. How is it that no one has come forward to say ‘I haven’t spoken or heard from X in so many weeks, it’s been four weeks’… how is that possible?

Mendoza says that “the right set of factors would have to come together for people to notice that the child was missing for a period of time, and we’re entering that period, where people are back from vacation, or they can ask a question like I haven’t seen that child in 2 or 3 or 4 weeks, and that does seem strange. I think someone still will come forward. I think there’s a good reason to believe that the case will be solved, but it’s going to require some good old-fashioned police work.”