Officers were called to the 100 block of West Orange Avenue at about 10 p.m. on a report of an assault with a deadly weapon.
A man told police he was driving with his wife and son when he saw two men a woman arguing on the sidewalk. One of the men hit the woman and then approached the victims' vehicle with a baseball bat, police said.
The suspect struck a rear window with the bat and shattered it. The victim's son, who was sitting in the back seat, suffered a minor cut.
The attacker had fled by the time police arrived. He is described as a clean-shaven Hispanic man about 25 years old, 5 feet 4 inches tall with a medium build and short, dark hair. He was wearing a red T-shirt and red shorts.