Investigators said Carlos Anibal Lopez got into an argument with his wife, Xiomara Lopez, just before he shot her. Their 11-year-old son was grazed by a bullet. The child is now in the hospital in stable condition.
Police said the man's wife was holding their 3-year-old daughter when she was shot in the head. The child was not injured. The couple's 7-year-old daughter also witnessed the shooting and gave police and account of what happened.
County child welfare authorities were called to take care of the children.
Lopez is believed to have fled the scene in a late 80's model Toyota Corolla. He is described as a Hispanic man, about 5 feet-4 inches tall and weighing 124 pounds.
Anyone with information about the shooting is asked to call the Northwest Police Division at 213-485-2582.