A suicide note has been found after the bodies of a young girl and her father were pulled from the Parramatta River on Saturday.

Police believe the six-year-old may have been deliberately thrown in the water from a hire boat by the man in a horrific act of domestic violence.

“We have uncovered a suicide note and some other evidence drawing us to this conclusion,” NSW Police Marine Area Commander, Superintendent Joe McNulty, told 2GB on Monday.

Officers were called to Hen and Chicken Bay at Concord, in Sydney’s inner west, about 11.45am on Saturday following reports of man’s body floating in the river.

They used a private boat to retrieve the 47-year-old, but he was unable to be revived.

Reports that a young girl was also there prompted a widespread search. Some hours later, her body was also recovered from the water.

The bodies of two people have been pulled from the Parramatta River. Photo: Seven screenshot

Police used CCTV images of the incident from a nearby home to help direct divers to find the little girl’s body.

The man was not known to police and had no recorded history of domestic violence, leaving police with the difficult job of unravelling what occurred.

“We’re trying to make sense of this senseless crime,” McNulty said.

“We really need to make sense of this, because it is a complex investigation.”

McNulty said officers were immediately suspicious about the circumstances of the incident because life jackets were on board the boat but had not been used.

“It just didn’t stack up,” he said.

The girl’s mother was notified and was on the scene during the search for her daughter.

“At this stage it’s horrible but we’re wrapping so much care around the victim and the mother that’s been left behind,” McNulty said.

The girl was the couple’s only child, NSW Police Burwood Command Superintendent Christine McDonald told media on Saturday.

“Obviously, a mother in this situation … it would rock any mother to the core,” she said.

A friend of the man had contacted police an hour after his body was found with concerns for the father and daughter’s welfare, police said.

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-AAP