Third arrest in Sydney car park killing

A Sydney man was allegedly lured to his death by a 27-year-old woman posing as a buyer for items he had advertised online.

Ross Houllis, 28, died in hospital after he was savagely beaten and robbed by two men at a shopping centre in Wakeley, police say.

Mr Houllis had turned up at the shopping centre on February 14 to meet a buyer for items he had advertised for sale on the internet.

Sami Hamdach, 27, and Abdul Karaali, 26, allegedly demanded cash from Mr Houllis before beating him to the ground and dragging him through the Bulls Road car park.

The pair were in February charged with murdering Mr Houllis and remain before the courts.

Detectives on Thursday morning arrested a 27-year-old woman in Bankstown and also charged her with murder.

The woman lured Mr Houllis to the shopping centre so Hamdach and Karaali could assault and rob him, police say.

She has been refused bail and is currently under police guard in hospital.

Police have previously described the attack as "horrific".

"The level of violence, it was cold, it was calculating, it was very deliberate," Superintendent Brett McFadden said in February.

"It's something that's just unacceptable for our society."