2 Samuel 2:23 However, he refused to turn aside; therefore Abner struck him in the belly with the butt end of the spear, so that the spear came out at his back. And he fell there and died on the spot. And it came about that all who came to the place where Asahel had fallen and died, stood still.

2 Samuel 3:27 So when Abner returned to Hebron, Joab took him aside into the middle of the gate to speak with him privately, and there he struck him in the belly so that he died on account of the blood of Asahel his brother.

1 Kings 2:5 "Now you also know what Joab the son of Zeruiah did to me, what he did to the two commanders of the armies of Israel, to Abner the son of Ner, and to Amasa the son of Jether, whom he killed; he also shed the blood of war in peace. And he put the blood of war on his belt about his waist, and on his sandals on his feet. (NASB ©1995)