Investigators spent the night searching a foster home in the central Massachusetts town of Auburn, where two toddler girls were found unresponsive on Saturday.
A 2-year-old died, and a second foster child, a 22-month-old girl, remains hospitalized in what the district attorney called "dire" condition.
Investigators are looking into dozens of 911 calls to the home since 2008.
That prompted Gov. Charlie Baker to say Tuesday that 911 calls could become a consideration when someone applies to be a foster parent.
"Do we believe that as part of the process going forward we should check the 911 data? I think that's a really good question and it's one of the questions we've raised with the department," Baker told reporters, but then added he also doesn't want to punish people for reporting crimes.
Baker said Tuesday that in the current Department of Children and Families cases under investigation — in Hardwick, where a 7-year-old is now in a coma, and Auburn — the families were being monitored.
"In both these cases there was a lot of oversight, a lot of visits, a lot of eyes on kids, which is one of the things we talked ... about right out of the gate, and yet here we are," Baker said. "Clearly we have to do better."
The head of DCF, Linda Spears, broke her silence on the cases, telling The Boston Herald that they need to focus on Central Massachusetts offices.
"We have a pretty challenging population to serve in that region of state."