'Murderer' in the Bible

And Elisha sat in his house, and the elders sat with him. And the king sent a man before him. Before the messenger came to him, he himself said to the elders, Do ye see how this son of a murderer has sent to take away my head? See, when the messenger comes; shut the door, and keep him off with the door: is not the sound of his master's feet behind him?

And when Jehu came in at the gate, she said, Is it peace, Zimri, murderer of his master?