[NYer]

I wonder why those studying this find are so sure the infants were murdered?

As the story notes:

Measurements of their bones show all the babies died at around 40 weeks gestation, suggesting very soon after birth. If they had died from natural causes, they would have been different ages.

[Tammy8]

I read that, but if they were stillborn, or had major birth defects they still would have died at about 40 weeks- ahhh.. who knows.