The child's body didn't show any apparent signs of trauma and it's not clear whether or not she was murdered, Procopio told Crimesider. However, after her information was shared with the National Center for Missing and Exploited Children and state and local jurisdictions across the country, Procopio said state police can't find any corresponding missing persons reports.
A preliminary autopsy has been completed, but toxicology results are still pending, Procopio said. The state police crime lab has begun the process of extracting DNA, working with an academic lab, though results could take some time, he said. The child's DNA would then be compared to state databases that require DNA sample submission for those convicted of certain crimes.
http://www.cbsnews.com/news/officials-family-may-know-about-massachusetts-baby-does-death/
How could they not be clear if she was murdered?
They haven't got a cause of death. It could have been accidental - for example, she could have gotten into cleaning supplies. I suppose it could have even been an allergic reaction (would that show in an autopsy?) and parents here illegally didn't know what to do and panicked.