1 Chronicles 10:5-9

When his armor bearer saw that Saul was dead, he likewise fell on his sword and died.

So Saul died with his three sons, and all those of his house died together.

When all the people of Israel who were in the valley saw that they had fled, and that Saul and his sons were dead, they abandoned their cities and fled; and the Philistines came and lived in them.

It came about the next day, when the Philistines came to strip those killed, that they found Saul and his sons fallen on Mount Gilboa.

So they stripped him and took his head and his armor and sent messengers around the land of the Philistines to carry the good news to their idols and to the people.