This tempel is from a few hundred years bc to a couple of hundred years ad, and was extended and used by three different cultures. The first and the second constructed the pyramid formed temple and the third buried their dead in it.
The graves contain people wrapped in cloth, sitting in fetal position. This was quite common in Indian burials, it is assumed that it symbolized a “new birth” into the realm of the dead. Furthermore there were burial gifts, also common. But there have also been found corpses of small children in some graves. The scientific explanation for this is that the newborn child comes from “the other side”, and still has memories of how to get there, thus being able to help the buried grown-up to find a safe passage.
We of course think it’s horrendous to sacrifice toddlers, but for these people death was just another form of life, but in another dimension. They would always, sooner or later come back again to this world.