A Sydney woman has been stabbed to death by her former partner, who also died of stab wounds.

Family in the home in Tongariro Terrace, Bidwill, were witnesses to the stabbing about 12.45pm on Saturday, police said.

“Some intervened in what was happening,” Detective Chief Inspector Paul Tickner told reporters.

The female victim, 22, found outside the home by police was treated for multiple stab wounds, including to her stomach, but died shortly after arriving at Westmead Hospital.

Her male attacker was found with chest wounds inside the home and died at the scene.

“There may have been some kind of split in recent times and they were trying to get back together,” Det Insp Tickner said.

“It’s a tragic loss of life. They were only 22 years old – they had their whole life in front of them.

“Both families are tragically suffering because of this.”

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