2 Samuel 3:27
And when Abner was returned to Hebron, Joab took him aside in the gate to speak with him quietly, and smote him there under the fifth rib, that he died, for the blood of Asahel his brother.
Torrey's Topical Textbook—AKJV

1 Kings 2:5,28-33
Moreover you know also what Joab the son of Zeruiah did to me, and what he did to the two captains of the hosts of Israel, to Abner the son of Ner, and to Amasa the son of Jether, whom he slew, and shed the blood of war in peace, and put the blood of war on his girdle that was about his loins, and in his shoes that were on his feet.
Torrey's Topical Textbook—AKJV