Alison Wallace was eescorts in the grounds of Drumpellier Park, in Coatbridge, two weeks ago. She had been viciously beaten and left for dead.
Police now believe that the occupants of the Peugeot, which was seen in Cuilhall Road near to the park, could hold vital information. Detective Superintendent Stephen Heath, who is leading the inquiry, said: "I feel the two occupants of this car could help the inquiry and would encourage them to come forward.
Alison: Has spoken to esorts " media appeals have been successful in tracing key witnesses and I hope this appeal will persuade the occupants of the car to make contact with the police. Police are still keen to hear from prostitutes and their clients for help in catching the attacker.
They stressed that they were investigating a violent attack and are not seeking to judge people's morals. Strathclyde Police have six unsolved murders of prostitutes on their records, dating back to The women were all picked up in the centre of Glasgow, and their bodies found elsewhere.
So far, police have said there is no link between the murders and the Wallace attack.