אֵ֗לֶּה בִּקְשׁ֧וּ כְתָבָ֛ם הַמִּתְיַחְשִׂ֖ים וְלֹ֣א נִמְצָ֑א וַיְגֹֽאֲל֖וּ מִן־הַכְּהֻנָּֽה׃
These sought their register, that is, the genealogy, but it was not found; therefore were they deemed polluted and put from the priesthood.
Read halakhic rulings (Jewish law) on Nehemiah 7:64: and classical halakhic sources.