David learns of Saul's death

In the book of 2 Samuel, chapter 1, David learns that Saul is dead.

The one who told David about Saul's death was an Amalekite who happened to be standing near Saul as the battle was closing in on him.  Saul ordered the Amalekite to kill him.  And he did.

When David hears of this, one of the Israelites was enraged and said, "Kill him!"

So they mortally wounded the Amalekite.

David said that it was because the Amalekite confessed to them all that he killed Saul, the Lord's chosen ruler over Israel.