Hills police are investigating a report that a gun was fired at a home in Box Hill on Saturday morning.
Police were called to a house on Boundary Road about 9.30am Saturday, responding to reports of a loud argument and possible gunshot.
A man and a woman were arrested at the scene as police allege drug paraphernalia was found.
They were taken to Castle Hill Police Station and later released.
Police later received information another man left the premises before officers arrived. No one was injured.