Deuteronomy 17:2-7

2If a man or woman living among you in one of the towns the Lord gives you is found doing evil in the eyes of the Lord your God in violation of his covenant, 3and contrary to my command has worshiped other gods, bowing down to them or to the sun or the moon or the stars in the sky, 4and this has been brought to your attention, then you must investigate it thoroughly. If it is true and it has been proved that this detestable thing has been done in Israel, 5take the man or woman who has done this evil deed to your city gate and stone that person to death. 6On the testimony of two or three witnesses a person is to be put to death, but no one is to be put to death on the testimony of only one witness. 7The hands of the witnesses must be the first in putting that person to death, and then the hands of all the people. You must purge the evil from among you.