Amasa was not on his guard against the dagger1 in Joab's2 hand, and Joab plunged it into his belly, and his intestines spilled out on the ground. Without being stabbed again, Amasa died. Then Joab and his brother Abishai pursued Sheba son of Bicri.
References for 2 Samuel 20:10
One of Joab's men stood beside Amasa and said, "Whoever favors Joab, and whoever is for David, let him follow Joab!"
Amasa lay wallowing in his blood in the middle of the road, and the man saw that all the troops came to a halt3 there. When he realized that everyone who came up to Amasa stopped, he dragged him from the road into a field and threw a garment over him.
References for 2 Samuel 20:12
After Amasa had been removed from the road, all the men went on with Joab to pursue Sheba son of Bicri.