וְעָבְר֤וּ הָעֹֽבְרִים֙ בָּאָ֔רֶץ וְרָאָה֙ עֶ֣צֶם אָדָ֔ם וּבָנָ֥ה אֶצְל֖וֹ צִיּ֑וּן עַ֣ד קָבְר֤וּ אֹתוֹ֙ הַֽמְקַבְּרִ֔ים אֶל־גֵּ֖יא הֲמ֥וֹן גּֽוֹג׃
And when they that pass through shall pass through the land, and any seeth a man’s bone, then shall he set up a sign by it, till the buriers have buried it in the valley of Hamon-gog.
Mishnah Niddah
They are believed when they say, "we buried miscarriages there," or "we did not bury them." They are believed when they say concerning a beast whether it had given birth to a firstling or had not given birth to one. They are believed when giving information on the marking of graves. But they are not believed either in regard to overhanging branches, or protruding stones or a bet ha-peras. This is the general rule: in any matter in which they are under suspicion they are not believed.