Authorities said Ruby Bing went to visit her mother and knocked at her front door while holding her 4-month-old baby.
Police said Adele Bing was still upset about the argument she had with Lane and thought he was the person knocking.
Investigators said Adele Bing armed herself with a baseball bat and a handgun, and as she opened the door, she fired a shot, hitting her daughter in the upper chest. The 4-month-old was not injured, but Ruby Bing died at the scene.
Police said Adele Bing charged with second-degree murder and child abuse without great bodily harm.
Bing was transported to the Polk County Jail.