The information widely circulated in mainstream media is pure propaganda.
The IDF had claimed that Hamas had decapitated 40 babies; the story then changed to 40 babies killed, and later to some babies allegedly decapitated and baked. This is fake news, part of the anti-Hamas propaganda war.
Haaretz reports that the IDF admitted to killing 112 civilians in Beeri, including one baby, who was a victim of the Hannibal Directive. This means that all those who died in Beeri were killed by the IDF, including the baby Mila Cohen. The baby was killed by the IDF.
The Hannibal Directive (or Hannibal Procedure) is an Israeli Defense Forces (IDF) directive aimed at preventing the capture of Israeli soldiers during combat. Israel does not negotiate with the enemy, even in hostage situations.
The proverb proves true: the first casualty in a war is the truth."