I seem to recall something in The Iliad about this practice. War prisoners from Troy to be buried at the feet of slain Greek heroes in the homeland?
The ones who fell face down into the dust, clanging in their armor?
The only incident similar in the Iliad was when Achilles sacrificed 10 (I think it was) Trojan youths before the funeral pyre of Patrocles.
And this was about six hundred years earlier.
Human sacrifice was extremely rare after the Sky gods were worshipped. This added to the horror of Agamemnon’s sacrifice of the daughter, Iphigenia to get the winds to get to Troy.