Teens charged with attempted murder after allegedly throwing woman into Hawkesbury River

The alleged victim, a 19-year-old woman from Campbelltown, told police she was thrown into the river while still tied up. Photo / Channel 7

A teen charged with attempted murder who police allege kidnapped, tortured and tossed a woman off a 30m bridge wrote on Facebook hours earlier: "Why do I do stupid sh*t?"

A 19-year-old woman and a 17-year-old girl, who cannot be named, allegedly held another 19-year-old woman against her will on Saturday night before assaulting her, driving her to Windsor Bridge, northeast of Sydney, and tossing her into the Hawkesbury River while she was tied up.

Police allege the victim, from Campbelltown, south of Sydney, managed to swim to the riverbank where she sought help. She was taken to Nepean Hospital for treatment.

The bridge from where a 19-year-old woman was allegedly thrown into the Hawkesbury River. Photo / News Corp

The teens are accused of kidnapping the 19-year-old from her home, placing her in the boot of a Holden Commodore and driving her from Ambervale to Whalen then on to Windsor, a journey of about 60km.

They were both charged with attempted murder, aggravated kidnapping, wounding a person with intent to cause grievous bodily harm and robbery.

Police from Hawkesbury yesterday seized a Holden Commodore from a home in Whalen and arrested the 19-year-old.

The 17-year-old girl attended Windsor Police Station about 2pm today where she was arrested.

The 19-year-old woman was refused bail yesterday after a brief appearance at the Penrith Local Court. She will be held in custody until her next appearance on November 23.

The 17-year-old girl was also refused bail to appear at a Children's Court tomorrow.