This is a perfectly legitimate question even though many alts don't believe the great pyramids
were tombs so it hardly seems to impinge on them to locate the kings' remains. But it is a fair
question since every indication is that the disposition of dead kings appears to be of supreme
interest to the builders as evidenced by the Pyramid Texts. One doesn't need to understand
the translations or the language to see that that the dead king is of great importance and they
wouldn't have lost, misplaced, or forgotten the remains.
I believe the Pyramid Texts are quite specific about how the mummy (dead king) was handled.
This work is simply ritual that was read aloud to the people at the various ceremonies involving
the ascension of the dead king. I believe they specifically stated in many lines that the king was
cremated in a ceremony but even if you don't accept that there is a coherent meaning to these
words it is still strongly implied that the body was cremated. The disposition of the ashes is no-
where mentioned and I believe this implies that they were not of great importance once the king
was reborn (essentially as the pyramid/ kingdom/ etc/ etc). This is presumptive and it's entire-
ly possible the remains were of at least minor import and they might have even been left in the
pyramid. But this is no minor point because the people did not believe these were tombs whet-
her the king was inside or not. Not one individual working on building the pyramid would consider
himself to be building a tomb. It was a house of life and not death. It was a living king(dom) and
not a tomb. There was no limit to the number of kings who might live in a great pyramid but the
number of dead kings was capped at "zero" in every single instance*.
* possibly excepting S1 (the first great pyramid).