Neighbors in Killarney Vale, a quiet suburb in the Central Coast region north of Sydney, alerted police after finding the little girl in the driveway, the Wolondilly Advertiser reported.
"They killed mummy and daddy," she was screaming.
The bodies of her parents, identified only as a 55-year-old man and his 45-year-old wife, were found inside. A suspect, Corey Breen, 25, was arrested nearby a short time later.
Breen was allegedly responsible for a string of crimes after leaving his house in nearby Gorokan during a violent confrontation with his partner. He allegedly stabbed a man during an attempted carjacking, attacked two men in a convenience store and stole two cars, in one case trying to get into a house as well.