She intervened in an assault on a bus.
Dorset police have released an image of a woman who challenged a man attacking a teenage girl.
The 15 year old was not hurt in the incident which happened on a bus in Bournemouth centre on 12th April.
The offender is described as a white man, approximately 35 to 45-years-old, slim build, with balding grey/black hair and a goatee beard, wearing dark sunglasses and a patterned sweater with a zip up front.
Detective Constable Stefanie Belton of Bournemouth CID, said: "We are very keen to speak to a woman who witnessed the assault and challenged the offender.
"She boarded the bus outside the Cyber Café on Charminster Road at approximately 12.18pm and following further enquires I am now able to release CCTV images.
"I would like to stress that this woman is not a suspect, but we are very keen to speak with her as we understand she may have seen something that will help with the investigation.”
The witness can be described as a white female with dark coloured hair, wearing a Sainsbury's uniform
DC Belton continued: "I urge anyone who may have any information to contact Dorset Police urgently”.
Witnesses and anyone with information should call Dorset Police in confidence on 101 quoting incident number 12:207. Alternatively, call the free and anonymous Crimestoppers line on 0800 555 111 where mobile phone tariffs may apply.