וַעֲתַלְיָ֙הוּ֙ אֵ֣ם אֲחַזְיָ֔הוּ רָאֲתָ֖ה כִּ֣י מֵ֣ת בְּנָ֑הּ וַתָּ֗קָם וַתְּדַבֵּ֛ר אֶת־כָּל־זֶ֥רַע הַמַּמְלָכָ֖ה לְבֵ֥ית יְהוּדָֽה׃
Now when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal of the house of Judah.
Read midrashic interpretation of II Chronicles 22:10: and classical rabbinic exegesis.