2 Samuel 3:24-27

24Then Joab went to the king and said, "What have you done? Behold, Abner came to you. Why is it that you have sent him away, so that he is gone?

25You know that Abner the son of Ner came to deceive you and to know your going out and your coming in, and to know all that you are doing."

26When Joab came out from David's presence, he sent messengers after Abner, and they brought him back from the cistern of Sirah. But David did not know about it.

27And when Abner returned to Hebron, Joab took him aside into the midst of the gate to speak with him privately, and there he struck him in the stomach, so that he died, for the blood of Asahel his brother.