Four people have been charged with the attempted murder of a 19-year-old woman in western Sydney.

Brooke Brown, 19, spent last night behind bars after being refused bail in the Penrith Court yesterday. ( Facebook )

Matthew Leuthwaite, 22, Brooke Brown, 19, a 17-year-old girl and a 16-year-old boy are accused of kidnapping and throwing Kayla Kendrigan off Windsor Bridge into the Hawkesbury River at the weekend.

A disturbing video shows the 19-year-old being tied to a chair before being dragged into a room at a house in Whalan on Saturday night.

The young woman was allegedly blindfolded, tied to a chair with an iPhone cable, and then punched, beaten with a wooden bat and stabbed multiple times.

On Sunday morning, the victim was allegedly forced into the boot of a car before being thrown into the Hawkesbury River.

Matthew Leuthwaite is one of four people facing charges. ( Source: Facebook )

Ms Kendrigan, who has learning difficulties and was born without a right arm, managed to swim to the riverbank before seeking help.

Police and paramedics were called to the scene and she was taken to the Nepean Hospital and treated for serious injuries.

The ABC understands the Gosford woman was kidnapped at a house in Campbelltown before she allegedly endured hours of torture at the Whalan property.

Mr Leuthwaite, Ms Brown and the teenage girl have been refused bail.

All three, along with the 16-year-old boy, are facing a string of charges, including attempted murder and aggravated kidnapping.

The victim's father thanked police in a Facebook status.

Ms Kendrigan's father Ian posted on Facebook, saying "I would like to say from the bottom of my heart a huge thank you to police and detectives you have done a fantastic job".

The accused are expected to face court again later this year.