1 Samuel 31:9

And they cut off his head - It is possible that they cut off the heads of his three sons likewise; for although only his head is said to be cut off, and his body only to be fastened to the walls of Beth-shan, yet we find that the men of Jabesh-gilead found both his body and the bodies of his three sons, fastened to the walls, 1 Samuel 31:12 .

Perhaps they only took off Saul's head, which they sent about to their temples as a trophy of their victory, when they sent the news of the defeat of the Israelites through all their coasts, and at last placed it in the temple of Dagon, 1 Chronicles 10:10 .