Prompted by new thinking from researchers, police are re-examining several cases of Sudden Infant Death Syndrome, looking for signs that the babies were instead victims of child abuse.
"We're contacting hospitals in the Boston area," said James Borghesani, spokesman for the district attorney's office. "We're making some inquiries."
In Chicago, prosecutors already have asked a grand jury to indict a woman in connection with the deaths of four of her children in the 1970s and 1980s who were classified as SIDS cases.
The probes come a month after the publication of "The Death of Innocents," a book that claims that about one-third of the 155 babies treated in Massachusetts General Hospital for repeated "near-miss" episodes of SIDS between 1972 and 1975 may have been abused.
In "near-miss" episodes, the child was suspected of having stopped breathing but survived.
Authors Richard Firstman and Jamie Talan cite a 1972 study that led many to believe SIDS ran in families, a theory rejected today by many researchers.
The study's conclusions were based in part on a spate of infant deaths in one family that were labeled as SIDS fatalities when in fact the mother had killed them all.