A police manhunt was under way tonight after a man fled the scene of a fatal stabbing in a taxi. [8 August 2012]

Detectives from West Midlands Police said the man ran away after a 22-year-old woman was repeatedly stabbed in Northfield, Birmingham, at around 8am.

The pair are believed to have been in a relationship, police said. They were both passengers in the taxi - a light coloured Peugeot car.

A police spokeswoman said the driver called 999 from the scene, on Dimsdale Road, but the woman was in cardiac arrest when paramedics arrived and could not be saved.

She has not been identified but police said she was local. A post mortem examination is expected to be conducted tomorrow.

A large number of police officers were in the area throughout the day and forensic investigators could be seen scouring the surrounding street and nearby gardens.

Detective Chief Inspector Wayne Jones said: "Officers have sealed off the scene of this incident, and are making significant enquiries in the local area as we search for the man who ran from the scene.

"We believe that the victim and the suspect are known to one another and one line of inquiry is that this incident is domestic related.

"The suspect we are searching for is described as a mixed-race Asian man, around 5ft 8in tall, in his 20s, with short black hair. He was wearing a dark jacket.

"We urge anyone who witnessed the incident or who has seen this man, to come forward and contact police."

Superintendent Andy Shipman, from Birmingham South Police, said there was no need for residents in the area to be "unduly concerned", adding:

"We urge local people to come forward to help with this investigation.

"Our officers are out in the area conducting house to house enquiries and speaking to members of the community to offer some reassurance to those distressed by this morning's events.

"Violent crime is very rare in south Birmingham and we hope local people can be reassured that this is being treated as an isolated incident between two people, at this stage of the investigation."

West Midlands Ambulance Service said a rapid response vehicle, an ambulance, a paramedic officer and the Midlands Air Ambulance from Cosford attended the scene.

A spokesman said: "The woman was in traumatic cardiac arrest with multiple stab wounds.

"Emergency treatment was immediately carried out, including specialist advanced life-support techniques.

"Unfortunately, despite the best efforts of all medics in attendance, nothing could be done to save the woman and she was confirmed dead at the scene."

Anyone with information to help the police inquiry is asked to call Force CID in Birmingham by dialling 101 or contact Crimestoppers on 0800 555 111.

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