Detectives investigating a sex assault on a teenage girl in Bidston are seeking information about a black or dark-coloured car believed to be a Peugeot 206.
Officers are trying to trace the 2000-2009 model, which has five doors and black wheels.
On Thursday, at around 3.50pm, the victim was walking along School Lane when she saw a man sitting in a dark-coloured car.
The man then got out of the car and subjected her to an indecent assault in an alleyway between School Lane and Keele Close.
The attacker is believed to have travelled from Bidston Village Road into Lennox Lane where he stopped in School Lane.
He was white, of slim build, with dark eyes.
Detective Inspector Mark Tivendale said "This is a disgraceful attack on a schoolgirl making her way home.
"I'd like to reassure the public that incidents such as this are rare but we are taking this report extremely seriously and are working hard to identify the offender.
"We are particularly keen to speak to anyone who was in the area at the time, anyone who recognizes the description of the car or has information about the driver to come forward.
"Any information, no matter how small, could assist our inquiry."
CCTV is being examined from the area and inquiries continue.
Anyone with information about this incident should contact Birkenhead CID on 777 2265 or Crimestoppers anonymously on 0800