2 Kings 10:6-8

6Then he wrote a letter the second time to them, saying, If ye are mine, and if ye will hearken to my voice, take ye the heads of the men your master’s sons, and come to me to Jezreel by to morrow this time. Now the king’s sons, being seventy persons, were with the great men of the city, who brought them up.1

7And it came to pass, when the letter came to them, that they took the king’s sons, and slew seventy persons, and put their heads in baskets, and sent them to him to Jezreel.

8And there came a messenger, and told him, saying, They have brought the heads of the king’s sons. And he said, Lay ye them in two heaps at the entrance of the gate until the morning.